Build: New build option to enable combined build for ITS and PS Arch tests.

New option   : -DPSA_API_TEST_STORAGE=ON

Example usage: -DPSA_API_TEST_INTERNAL_TRUSTED_STORAGE=ON
               -DPSA_API_TEST_PROTECTED_STORAGE=ON
               -DPSA_API_TEST_STORAGE=ON

Change-Id: Ib3dbe7d5e7e8281855b7b7c6021820ef2dedfa4b
Signed-off-by: Vinay Kumar Kotegowder <vinaykumar.kotegowder@arm.com>
diff --git a/docs/user_guides/tfm_build_instruction.rst b/docs/user_guides/tfm_build_instruction.rst
index 44f0b0a..77666c9 100644
--- a/docs/user_guides/tfm_build_instruction.rst
+++ b/docs/user_guides/tfm_build_instruction.rst
@@ -96,6 +96,7 @@
 
     -DPSA_API_TEST_INTERNAL_TRUSTED_STORAGE=ON
     -DPSA_API_TEST_PROTECTED_STORAGE=ON
+    -DPSA_API_TEST_STORAGE=ON
     -DPSA_API_TEST_CRYPTO=ON
     -DPSA_API_TEST_INITIAL_ATTESTATION=ON