scsi: target: pscsi: Fix warning in pscsi_complete_cmd()

This fixes a compilation warning in pscsi_complete_cmd():

     drivers/target/target_core_pscsi.c: In function ‘pscsi_complete_cmd’:
     drivers/target/target_core_pscsi.c:624:5: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
     ; /* XXX: TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE */

Link: https://lore.kernel.org/r/20210228055645.22253-5-chaitanya.kulkarni@wdc.comReviewed-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_pscsi.c

@@ -620,8 +620,9 @@ static void pscsi_complete_cmd(struct se_cmd *cmd, u8 scsi_status,
 			unsigned char *buf;
 
 			buf = transport_kmap_data_sg(cmd);
-			if (!buf)
+			if (!buf) {
 				; /* XXX: TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE */
+			}
 
 			if (cdb[0] == MODE_SENSE_10) {
 				if (!(buf[3] & 0x80))