fix(notifications): flag that Must Be Zero

According to FF-A v1.1 EAC0 specification the bits [31:4] of the 'flags'
argument to the FFA_NOTIFICATION_GET ABI Must Be Zero.

Change-Id: I6381d9572eb8d7f7af700833c26ced59493a36b0
Signed-off-by: J-Alves <joao.alves@arm.com>
diff --git a/src/arch/fake/hypervisor/ffa.c b/src/arch/fake/hypervisor/ffa.c
index efd270b..f4bbd36 100644
--- a/src/arch/fake/hypervisor/ffa.c
+++ b/src/arch/fake/hypervisor/ffa.c
@@ -171,8 +171,9 @@
 }
 
 bool plat_ffa_is_notification_get_valid(struct vcpu *current,
-					ffa_vm_id_t receiver_id)
+					ffa_vm_id_t receiver_id, uint32_t flags)
 {
+	(void)flags;
 	(void)current;
 	(void)receiver_id;
 	return false;