svcrdma: fix an incorrect check on -E2BIG and -EINVAL

The current check will always be true and will always jump to
err1, this looks dubious to me. I believe && should be used
instead of ||.

Detected by CoverityScan, CID#1450120 ("Logically Dead Code")

Fixes: 107c1d0a991a ("svcrdma: Avoid Send Queue overflow")
Signed-off-by: Colin Ian King <[e-mail]>
Reviewed-by: Chuck Lever <[e-mail]>
Signed-off-by: J. Bruce Fields <[e-mail]>

net/sunrpc/xprtrdma/svc_rdma_sendto.c

···
 	return 0;
 
  err2:
-	if (ret != -E2BIG || ret != -EINVAL)
+	if (ret != -E2BIG && ret != -EINVAL)
 		goto err1;
 
 	ret = svc_rdma_post_recv(rdma, GFP_KERNEL);