feat(fvp): implement platform function to measure and publish Public Key

Implemented 'plat_mboot_measure_key' platform function for FVP platform
to measure and publish the public key information via RSS.

Change-Id: I0c9d6d6ac3650a939437e9331ed3c9246f242830
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/plat/arm/board/fvp/fvp_common_measured_boot.c b/plat/arm/board/fvp/fvp_common_measured_boot.c
index 7419e5e..0c1d5e7 100644
--- a/plat/arm/board/fvp/fvp_common_measured_boot.c
+++ b/plat/arm/board/fvp/fvp_common_measured_boot.c
@@ -45,3 +45,10 @@
 
 	return rc;
 }
+
+int plat_mboot_measure_key(const void *pk_oid, const void *pk_ptr,
+			   size_t pk_len)
+{
+	return rss_mboot_set_signer_id(fvp_rss_mboot_metadata, pk_oid, pk_ptr,
+				       pk_len);
+}