drivers: firmware: Handle error case in the zynqmp_pm_feature

Unhandled error coming from xilinx_pm_request() but return
value is not read back that's why getting sparse warning
as below:
warning: variable 'ret' set but not used [-Wunused-but-set-variable].
In case of error return the "ret" value.

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Link: https://lore.kernel.org/r/20231011025647.17200-1-venkatesh.abbarapu@amd.com
Signed-off-by: Michal Simek <michal.simek@amd.com>
diff --git a/drivers/firmware/firmware-zynqmp.c b/drivers/firmware/firmware-zynqmp.c
index 43fb7fa..8ea15c7 100644
--- a/drivers/firmware/firmware-zynqmp.c
+++ b/drivers/firmware/firmware-zynqmp.c
@@ -203,6 +203,8 @@
 	/* Check feature check API version */
 	ret = xilinx_pm_request(PM_FEATURE_CHECK, api_id, 0, 0, 0,
 				ret_payload);
+	if (ret)
+		return ret;
 
 	/* Return feature check version */
 	return ret_payload[1] & FIRMWARE_VERSION_MASK;