HID: fix hid_device_id for cross compiling

struct hid_device_id contains hidden padding which is bad for cross
compiling.  Make the padding explicit and consistent across
architectures.

Signed-off-by: Andreas Schwab <schwab@suse.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

include/linux/mod_devicetable.h

@@ -135,6 +135,7 @@ struct usb_device_id {
 
 struct hid_device_id {
 	__u16 bus;
+	__u16 pad1;
 	__u32 vendor;
 	__u32 product;
 	kernel_ulong_t driver_data