w1: ds2490: constify usb_device_id and fix space before '[' error

usb_device_id are not supposed to change at runtime. All functions
working with usb_device_id provided by <linux/usb.h> work with
const usb_device_id. So mark the non-const structs as const.

Fix checkpatch.pl error:
ERROR: space prohibited before open square bracket '['.
Signed-off-by: NArvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/w1/masters/ds2490.c

@@ -1088,7 +1088,7 @@ static void ds_disconnect(struct usb_interface *intf)
 	kfree(dev);
 }
 
-static struct usb_device_id ds_id_table [] = {
+static const struct usb_device_id ds_id_table[] = {
 	{ USB_DEVICE(0x04fa, 0x2490) },
 	{ },
 };