Docs: some clean-up to platform folder

- Remove support platform list from integration guide. Only keep the
  list under platform folder.
  Otherwise platform vendors have to maintain two lists and information
  can be duplicated or misaligned.
- Refine Arm platform doc structure to put OpenAMP docs under
  Corstone-1000
- Refine Cypress PSoC64 doc structure to move library docs under the
  PSoC64 list.

Change-Id: I7fad8dd1eb52594d406f6be8a61c38c27fcb72ff
Signed-off-by: David Hu <david.hu@arm.com>
diff --git a/platform/ext/index.rst b/platform/ext/index.rst
index 2e0633c..4aea392 100644
--- a/platform/ext/index.rst
+++ b/platform/ext/index.rst
@@ -16,7 +16,7 @@
     :caption: arm
     :glob:
 
-    target/arm/**
+    target/arm/index
 
 .. toctree::
     :maxdepth: 1
@@ -30,7 +30,7 @@
     :caption: Cypress
     :glob:
 
-    target/cypress/**
+    target/cypress/psoc64/index
 
 .. toctree::
     :maxdepth: 1
diff --git a/platform/ext/platform_introduction.rst b/platform/ext/platform_introduction.rst
index b895e29..b9e043e 100644
--- a/platform/ext/platform_introduction.rst
+++ b/platform/ext/platform_introduction.rst
@@ -30,7 +30,7 @@
           <https://developer.arm.com/tools-and-software/development-boards/fpga-prototyping-boards/mps3>`_
         - `LPC55S69.
           <https://www.nxp.com/products/processors-and-microcontrollers/arm-microcontrollers/general-purpose-mcus/lpc5500-cortex-m33/lpcxpresso55s69-development-board:LPC55S69-EVK>`_
-        - 'B-U585I-IOT02A.
+        - `B-U585I-IOT02A.
           <https://www.st.com/en/evaluation-tools/B-U585I-IOT02A.html>`_
         - `NUCLEO L552ZE Q.
           <https://www.st.com/content/st_com/en/products/evaluation-tools/product-evaluation-tools/mcu-mpu-eval-tools/stm32-mcu-mpu-eval-tools/stm32-nucleo-boards/nucleo-l552ze-q.html>`_
diff --git a/platform/ext/target/arm/corstone1000/index.rst b/platform/ext/target/arm/corstone1000/index.rst
new file mode 100755
index 0000000..9e3136b
--- /dev/null
+++ b/platform/ext/target/arm/corstone1000/index.rst
@@ -0,0 +1,13 @@
+Arm Corstone-1000
+=================
+
+.. toctree::
+    :maxdepth: 1
+    :glob:
+
+    readme.rst
+    openamp/**
+
+--------------
+
+*Copyright (c) 2022, Arm Limited. All rights reserved.*
diff --git a/platform/ext/target/arm/index.rst b/platform/ext/target/arm/index.rst
new file mode 100755
index 0000000..3e71053
--- /dev/null
+++ b/platform/ext/target/arm/index.rst
@@ -0,0 +1,14 @@
+Arm platforms
+=============
+
+.. toctree::
+    :maxdepth: 1
+    :glob:
+
+    corstone1000/index
+    mps3/**
+    musca_b1/**
+
+--------------
+
+*Copyright (c) 2022, Arm Limited. All rights reserved.*
diff --git a/platform/ext/target/cypress/psoc64/cypress_psoc64_spec.rst b/platform/ext/target/cypress/psoc64/cypress_psoc64_spec.rst
index 9d88b43..045f79b 100644
--- a/platform/ext/target/cypress/psoc64/cypress_psoc64_spec.rst
+++ b/platform/ext/target/cypress/psoc64/cypress_psoc64_spec.rst
@@ -183,9 +183,8 @@
 Signing
 *******
 
-############
 Signing keys
-############
+============
 
 Copy secure keys used in the board provisioning process to
 platform/ext/target/cypress/psoc64/security/keys:
@@ -236,9 +235,8 @@
 
     cysecuretools -t cy8ckit-064s0s2-4343w -p policy/policy_multi_CM0_CM4_tfm.json re-provision-device
 
-##################
 Signing the images
-##################
+==================
 
 Sign the images using CySecureTools CLI tool.
 Note: the tool overwrites unsigned file with a signed one, it also creates an
diff --git a/platform/ext/target/cypress/psoc64/index.rst b/platform/ext/target/cypress/psoc64/index.rst
new file mode 100755
index 0000000..d4f6d00
--- /dev/null
+++ b/platform/ext/target/cypress/psoc64/index.rst
@@ -0,0 +1,19 @@
+Cypress PSoC64
+==============
+
+.. toctree::
+    :maxdepth: 1
+    :caption: Specifics
+
+    cypress_psoc64_spec.rst
+
+.. toctree::
+    :maxdepth: 1
+    :caption: Libraries
+    :glob:
+
+    libs/**
+
+--------------
+
+*Copyright (c) 2022, Arm Limited. All rights reserved.*