feat(fake_host): create, enter and destroy a realm

Change-Id: I16924d42e1085a759d289961026bb3b9f52cf39f
Signed-off-by: Mate Toth-Pal <mate.toth-pal@arm.com>
diff --git a/plat/host/common/src/host_utils.c b/plat/host/common/src/host_utils.c
index 5dc8038..263f518 100644
--- a/plat/host/common/src/host_utils.c
+++ b/plat/host/common/src/host_utils.c
@@ -161,6 +161,12 @@
 				INPLACE(ID_AA64ISAR0_EL1_RNDR, 1UL));
 
 	/*
+	 * Add callback to elr_el2 so that the realm entry point can be accessed
+	 * by host_run_realm
+	 */
+	ret = host_util_set_default_sysreg_cb("elr_el2", 0UL);
+
+	/*
 	 * Only check the return value of the last callback setup, to detect
 	 * if we are out of callback slots.
 	 */