scsi: aacraid: rcode is unsigned and should be signed int

aac_fib_send can return -ve error returns and hence rcode should be
signed. Currently the rcode >= 0 check is always true and -ve errors are
not being checked.

Thanks to Dan Carpenter for spotting my original broken fix to this
issue.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Reviewed-by: NRaghava Aditya Renukunta <RaghavaAditya.Renukunta@microsemi.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/aacraid/aachba.c

@@ -1798,7 +1798,7 @@ int aac_report_phys_luns(struct aac_dev *dev, struct fib *fibptr, int rescan)
 	struct sgmap64 *sg64;
 	dma_addr_t addr;
 	u32 vbus, vid;
-	u32 rcode = 0;
+	int rcode = 0;
 
 	/* Thor SA Firmware -> CISS_REPORT_PHYSICAL_LUNS */
 	fibsize = sizeof(struct aac_srb) - sizeof(struct sgentry)