readme: Add support for SGI-575 platform in readme.rst

FVP_CSS_SGI-575 is the Fixed Virtual Platform on which the
Trusted-Firmware-A Tests are executed for SGI-575.

Change-Id: I606d316d251e69f5a88208b4edde132d29856b3d
Signed-off-by: Chandni Cherukuri <chandni.cherukuri@arm.com>
diff --git a/readme.rst b/readme.rst
index b27a070..1512545 100644
--- a/readme.rst
+++ b/readme.rst
@@ -91,6 +91,15 @@
 
 NOTE: Unless otherwise stated, the model version is version 11.4, build 37.
 
+System Guidance for Infrastructure Fixed Virtual Platforms
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+The AArch64 build has been tested on the following SGI Fixed Virtual Platforms
+(`FVP`_):
+-  ``FVP_CSS_SGI-575``
+
+NOTE: For ``FVP_CSS_SGI-575``, the model version is 11.4, build 40
+
 Still to come
 `````````````