feat(rmm) : use shared data buf to pass arg to rec

Host can pass arguments to rec using
per rec shared buffer.

Change-Id: Ic34acf6253031b3b5f184669084f15460b0fc5fd
Signed-off-by: Shruti Gupta <shruti.gupta@arm.com>
diff --git a/realm/realm_payload_main.c b/realm/realm_payload_main.c
index 586d400..b8c27bd 100644
--- a/realm/realm_payload_main.c
+++ b/realm/realm_payload_main.c
@@ -25,7 +25,7 @@
  */
 static void realm_sleep_cmd(void)
 {
-	uint64_t sleep = realm_shared_data_get_my_host_val(HOST_SLEEP_INDEX);
+	uint64_t sleep = realm_shared_data_get_my_host_val(HOST_ARG1_INDEX);
 
 	realm_printf("Realm: going to sleep for %llums\n", sleep);
 	waitms(sleep);