feat(fwu): add a config flag for including image info in the FWU metadata

The version 2 of the FWU metadata structure is designed such that the
information on the updatable images can be omitted from the metadata
structure. Add a configuration flag, PSA_FWU_METADATA_FW_STORE_DESC,
which is used to select whether the metadata structure has this
information included or not. It's value is set to 1 by default.

Change-Id: I4463a20c94d2c745ddb0b2cc8932c12d418fbd42
Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
diff --git a/Makefile b/Makefile
index 6a1ea99..53d391e 100644
--- a/Makefile
+++ b/Makefile
@@ -1185,6 +1185,7 @@
 	COT_DESC_IN_DTB \
 	USE_SP804_TIMER \
 	PSA_FWU_SUPPORT \
+	PSA_FWU_METADATA_FW_STORE_DESC \
 	ENABLE_MPMM \
 	ENABLE_MPMM_FCONF \
 	FEATURE_DETECTION \
@@ -1360,6 +1361,7 @@
 	NR_OF_FW_BANKS \
 	NR_OF_IMAGES_IN_FW_BANK \
 	PSA_FWU_SUPPORT \
+	PSA_FWU_METADATA_FW_STORE_DESC \
 	ENABLE_BRBE_FOR_NS \
 	ENABLE_TRBE_FOR_NS \
 	ENABLE_SYS_REG_TRACE_FOR_NS \