usb-uas: set max_lun and max_channel

256 luns is what the sam-4 address method 0 can handle and what
the qemu uas emulation supports.  So pick that for now.

[ v2: unlike the other two max_* fields max_channel isn't max+1 ]
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/storage/uas.c

@@ -991,6 +991,8 @@ static int uas_probe(struct usb_interface *intf, const struct usb_device_id *id)
 
 	shost->max_cmd_len = 16 + 252;
 	shost->max_id = 1;
+	shost->max_lun = 256;
+	shost->max_channel = 0;
 	shost->sg_tablesize = udev->bus->sg_tablesize;
 
 	devinfo->intf = intf;