scsi: scsi_dh_alua: Fix signedness bug in alua_rtpg()

stable inclusion
from linux-4.19.198
commit c021be62bbcbf5435ec89713ed542040196f5b89

--------------------------------

commit 80927822 upstream.

The "retval" variable needs to be signed for the error handling to work.

Link: https://lore.kernel.org/r/YLjMEAFNxOas1mIp@mwanda
Fixes: 7e26e3ea ("scsi: scsi_dh_alua: Check for negative result value")
Reviewed-by: NMartin Wilck <mwilck@suse.com>
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/scsi/device_handler/scsi_dh_alua.c

@@ -522,7 +522,8 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 	struct alua_port_group *tmp_pg;
 	int len, k, off, bufflen = ALUA_RTPG_SIZE;
 	unsigned char *desc, *buff;
-	unsigned err, retval;
+	unsigned err;
+	int retval;
 	unsigned int tpg_desc_tbl_off;
 	unsigned char orig_transition_tmo;
 	unsigned long flags;