feat(notifications): notifications set and get

Handle FF-A calls FFA_NOTIFICATION_SET and FFA_NOTIFICATION_GET.
The former is used for a sender to signal a notification to the
receiver; the latter is for the receiver to get whichever notifications
there are pending.

Change-Id: I7e9db94201d0d78ceecd599cd350eeb37a8cb1f8
Signed-off-by: J-Alves <joao.alves@arm.com>
diff --git a/inc/hf/api.h b/inc/hf/api.h
index be3903d..59755a4 100644
--- a/inc/hf/api.h
+++ b/inc/hf/api.h
@@ -106,3 +106,11 @@
 	ffa_vm_id_t sender_vm_id, ffa_vm_id_t receiver_vm_id, uint32_t flags,
 	ffa_notifications_bitmap_t notifications, bool is_bind,
 	struct vcpu *current);
+
+struct ffa_value api_ffa_notification_set(
+	ffa_vm_id_t sender_vm_id, ffa_vm_id_t receiver_vm_id, uint32_t flags,
+	ffa_notifications_bitmap_t notifications, struct vcpu *current);
+
+struct ffa_value api_ffa_notification_get(ffa_vm_id_t receiver_vm_id,
+					  uint16_t vcpu_id, uint32_t flags,
+					  struct vcpu *current);