nvmet-auth: fix return value check in auth receive

nvmet_auth_challenge() return type is int and currently it uses status
variable that is of type u16 in nvmet_execute_auth_receive().

Catch the return value of nvmet_auth_challenge() into int and set the
NVME_SC_INTERNAL as status variable before we jump to error.

Reported-by: Dan Carpenter <[e-mail]>
Signed-off-by: Chaitanya Kulkarni <[e-mail]>
Reviewed-by: Sagi Grimberg <[e-mail]>
Reviewed-by: Hannes Reinecke <[e-mail]>
Signed-off-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

drivers/nvme/target/fabrics-cmd-auth.c

···
 		 ctrl->cntlid, req->sq->qid, req->sq->dhchap_step);
 	switch (req->sq->dhchap_step) {
 	case NVME_AUTH_DHCHAP_MESSAGE_CHALLENGE:
-		status = nvmet_auth_challenge(req, d, al);
-		if (status < 0) {
+		if (nvmet_auth_challenge(req, d, al) < 0) {
 			pr_warn("ctrl %d qid %d: challenge error (%d)\n",
 				ctrl->cntlid, req->sq->qid, status);
 			status = NVME_SC_INTERNAL;