staging: rts5208: Change data type to unsigned int.

This patch fixes a minor checkpatch warning:

"WARNING: Prefer 'unsigned int' to bare use of 'unsigned'"
Signed-off-by: NLouie Lu <louie.lu@hopebaytech.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rts5208/rtsx_scsi.c

@@ -1518,7 +1518,7 @@ static int write_host_reg(struct scsi_cmnd *srb, struct rtsx_chip *chip)
 
 static int set_variable(struct scsi_cmnd *srb, struct rtsx_chip *chip)
 {
-	unsigned lun = SCSI_LUN(srb);
+	unsigned int lun = SCSI_LUN(srb);
 
 	if (srb->cmnd[3] == 1) {
 		/* Variable Clock */