staging: rts5208: fix missing error check on call to rtsx_write_register

Currently the check on error return from the call to rtsx_write_register
is checking the error status from the previous call. Fix this by adding
in the missing assignment of retval.

Detected by CoverityScan, CID#709877

Fixes: fa590c222fba ("staging: rts5208: add support for rts5208 and rts5288")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rts5208/sd.c

@@ -4690,7 +4690,7 @@ int sd_execute_write_data(struct scsi_cmnd *srb, struct rtsx_chip *chip)
 			goto sd_execute_write_cmd_failed;
 		}
 
-		rtsx_write_register(chip, SD_BYTE_CNT_L, 0xFF, 0x00);
+		retval = rtsx_write_register(chip, SD_BYTE_CNT_L, 0xFF, 0x00);
 		if (retval != STATUS_SUCCESS) {
 			goto sd_execute_write_cmd_failed;
 		}