ftpm: fix branch-protection handling

Ensure the value of BRANCH_PROTECTION is properly propagated to
ms-tpm20-ref external component, so that the appropriate compilation
flags are set accordingly.

Change-Id: Iacb5b87675ca8cd2751500011d4b2931dad09591
Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>
diff --git a/external/ms_tpm/ms_tpm-init-cache.cmake.in b/external/ms_tpm/ms_tpm-init-cache.cmake.in
index ca17282..8efab1a 100644
--- a/external/ms_tpm/ms_tpm-init-cache.cmake.in
+++ b/external/ms_tpm/ms_tpm-init-cache.cmake.in
@@ -8,6 +8,8 @@
 set(CMAKE_INSTALL_PREFIX @BUILD_INSTALL_DIR@ CACHE STRING "")
 set(CMAKE_TOOLCHAIN_FILE @TS_EXTERNAL_LIB_TOOLCHAIN_FILE@ CACHE STRING "")
 
+set(BRANCH_PROTECTION @BRANCH_PROTECTION@ CACHE STRING "")
+
 set(TPM_EXTRA_DEFINITIONS @TPM_EXTRA_DEFINITIONS@ CACHE STRING "Defines coming from Trusted Services")
 set(TPM_EXTRA_INCLUDES @TPM_EXTRA_INCLUDES@ CACHE STRING "Include paths coming from Trusted Services")