feat(fwu): initialize FWU driver in BL2

Initialized FWU driver module in BL2 component under
build flag PSA_FWU_SUPPORT.

Change-Id: I08b191599835925c355981d695667828561b9a21
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/make_helpers/defaults.mk b/make_helpers/defaults.mk
index 53d9605..72f84b5 100644
--- a/make_helpers/defaults.mk
+++ b/make_helpers/defaults.mk
@@ -352,3 +352,6 @@
 # Build option to define number of images in firmware bank, used in firmware
 # update metadata structure.
 NR_OF_IMAGES_IN_FW_BANK		:= 1
+
+# Disable Firmware update support by default
+PSA_FWU_SUPPORT			:= 0