Build: Install crypto_platform.h for Crypto service

Header file crypto_platform.h is included by crypto.h, which is
installed when Crypto service is enabled. So crypto_platform.h also
needs to be installed.

Signed-off-by: Xinyu Zhang <xinyu.zhang@arm.com>
Change-Id: I6a439cc1db26ce8e180d91c93002987a142bfb7e
diff --git a/cmake/install.cmake b/cmake/install.cmake
index 69db5a3..5d516b9 100644
--- a/cmake/install.cmake
+++ b/cmake/install.cmake
@@ -79,6 +79,7 @@
                         ${INTERFACE_INC_DIR}/psa/crypto_compat.h
                         ${INTERFACE_INC_DIR}/psa/crypto.h
                         ${INTERFACE_INC_DIR}/psa/crypto_client_struct.h
+                        ${INTERFACE_INC_DIR}/psa/crypto_platform.h
                         ${INTERFACE_INC_DIR}/psa/crypto_sizes.h
                         ${INTERFACE_INC_DIR}/psa/crypto_struct.h
                         ${INTERFACE_INC_DIR}/psa/crypto_types.h