zynqmp: pm: Allow obtaining additional return values from FW

Allow reading more than just a single value from the message buffer.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
diff --git a/plat/xilinx/zynqmp/pm_service/pm_ipi.h b/plat/xilinx/zynqmp/pm_service/pm_ipi.h
index d92e648..108aef4 100644
--- a/plat/xilinx/zynqmp/pm_service/pm_ipi.h
+++ b/plat/xilinx/zynqmp/pm_service/pm_ipi.h
@@ -39,6 +39,6 @@
 			       uint32_t payload[PAYLOAD_ARG_CNT]);
 enum pm_ret_status pm_ipi_send_sync(const struct pm_proc *proc,
 				    uint32_t payload[PAYLOAD_ARG_CNT],
-				    unsigned int *value);
+				    unsigned int *value, size_t count);
 
 #endif /* _PM_IPI_H_ */