fix(notifications): remove declaration of unimplemented function

Change-Id: Iee6f2933b7b5e28378af38164ddccc3fdeb378dc
Signed-off-by: Federico Recanati <federico.recanati@arm.com>
diff --git a/inc/hf/arch/plat/ffa.h b/inc/hf/arch/plat/ffa.h
index dafafcd..52cbc44 100644
--- a/inc/hf/arch/plat/ffa.h
+++ b/inc/hf/arch/plat/ffa.h
@@ -100,9 +100,6 @@
 					ffa_notifications_bitmap_t *from_sp,
 					struct ffa_value *ret);
 
-bool plat_ffa_notifications_get_call(ffa_vm_id_t receiver_id, uint32_t vcpu_id,
-				     uint32_t flags, struct ffa_value *ret);
-
 /**
  * Checks whether managed exit is supported by given SP.
  */