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/make_helpers/defaults.mk b/make_helpers/defaults.mk
index 1802077..7fe8bf8 100644
--- a/make_helpers/defaults.mk
+++ b/make_helpers/defaults.mk
@@ -351,6 +351,14 @@
 # Disable Firmware update support by default
 PSA_FWU_SUPPORT			:= 0
 
+# Enable image description in FWU metadata by default when PSA_FWU_SUPPORT
+# is enabled.
+ifeq ($(PSA_FWU_SUPPORT),1)
+PSA_FWU_METADATA_FW_STORE_DESC	:= 1
+else
+PSA_FWU_METADATA_FW_STORE_DESC	:= 0
+endif
+
 # Dynamic Root of Trust for Measurement support
 DRTM_SUPPORT			:= 0