Platform: Move tfm_initial_attestation_key_material.c under template

Since tfm_initial_attestation_key_material.c acts as an example of
attestation key, put it under platform/ext/common/template like
other template files.

Change-Id: Ia72ba6b1ec71a1cf71257463f3e1e91279e0fb71
Signed-off-by: David Hu <david.hu@arm.com>
diff --git a/platform/ext/psoc64.cmake b/platform/ext/psoc64.cmake
index 318deca..b878b72 100644
--- a/platform/ext/psoc64.cmake
+++ b/platform/ext/psoc64.cmake
@@ -187,7 +187,7 @@
 if (NOT DEFINED BUILD_TARGET_HARDWARE_KEYS)
   message(FATAL_ERROR "Configuration variable BUILD_TARGET_HARDWARE_KEYS (true|false) is undefined!")
 elseif(BUILD_TARGET_HARDWARE_KEYS)
-  list(APPEND ALL_SRC_C_S "${PLATFORM_DIR}/common/tfm_initial_attestation_key_material.c")
+  list(APPEND ALL_SRC_C_S "${PLATFORM_DIR}/common/template/tfm_initial_attestation_key_material.c")
   list(APPEND ALL_SRC_C_S "${PLATFORM_DIR}/common/tfm_rotpk.c")
   list(APPEND ALL_SRC_C_S "${PLATFORM_DIR}/target/cypress/psoc64/dummy_crypto_keys.c")
 endif()