VHE: Add exception-level indication to manifest.

Added parsing of 'exception-level' from vm manifests. This field can be
used to indicate the exception level that a partition runs at. This
field follows the same format as the exception-level field of an FF-A
SP's manifest.

Change-Id: Ie03b9574b1e3c0b5b6d8620db31d0125121f23ad
Signed-off-by: Raghu Krishnamurthy <raghu.ncstate@gmail.com>
diff --git a/src/manifest.c b/src/manifest.c
index 6110765..1101081 100644
--- a/src/manifest.c
+++ b/src/manifest.c
@@ -343,6 +343,8 @@
 					 MANIFEST_INVALID_ADDRESS,
 					 &vm->primary.boot_address));
 	}
+	TRY(read_optional_uint8(node, "exception-level", (uint8_t)EL1,
+				(uint8_t *)&vm->sp.run_time_el));
 
 	return MANIFEST_SUCCESS;
 }