xilinx: zynqmp: synchronize firmware call return payload

Removes duplicated definition of PAYLOAD_ARG_CNT and define it in the
firmware driver. Additionally fixes payload buffer declarations without
macro usage

Signed-off-by: Ibai Erkiaga <ibai.erkiaga-elorza@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

include/zynqmp_firmware.h

@@ -77,6 +77,15 @@ enum pm_api_id {
 
 #define PMUFW_V1_0      ((1 << ZYNQMP_PM_VERSION_MAJOR_SHIFT) | 0)
 
+/*
+ * Return payload size
+ * Not every firmware call expects the same amount of return bytes, however the
+ * firmware driver always copies 5 bytes from RX buffer to the ret_payload
+ * buffer. Therefore allocating with this defined value is recommended to avoid
+ * overflows.
+ */
+#define PAYLOAD_ARG_CNT	5U
+
 unsigned int zynqmp_firmware_version(void);
 void zynqmp_pmufw_load_config_object(const void *cfg_obj, size_t size);
 int xilinx_pm_request(u32 api_id, u32 arg0, u32 arg1, u32 arg2,