scsi: csiostor: Fix wrong return value in csio_hw_prep_fw()

On an error exit path, a negative error code should be returned instead of
a positive return value.

Link: https://lore.kernel.org/r/20200802111531.5065-1-tianjia.zhang@linux.alibaba.com
Fixes: f40e74ff ("csiostor:firmware upgrade fix")
Cc: Praveen Madhavan <praveenm@chelsio.com>
Signed-off-by: NTianjia Zhang <tianjia.zhang@linux.alibaba.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/csiostor/csio_hw.c

@@ -2384,7 +2384,7 @@ static int csio_hw_prep_fw(struct csio_hw *hw, struct fw_info *fw_info,
 			FW_HDR_FW_VER_MICRO_G(c), FW_HDR_FW_VER_BUILD_G(c),
 			FW_HDR_FW_VER_MAJOR_G(k), FW_HDR_FW_VER_MINOR_G(k),
 			FW_HDR_FW_VER_MICRO_G(k), FW_HDR_FW_VER_BUILD_G(k));
-		ret = EINVAL;
+		ret = -EINVAL;
 		goto bye;
 	}