HID: surface-hid: Constify lowlevel HID driver

Since commit 52d22534 ("HID: Make lowlevel driver structs const")
the lowlevel HID drivers are only exposed as const.

Take advantage of this to constify the underlying structure, too.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230130-hid-const-ll-driver-v1-6-3fc282b3b1d0@weissschuh.netSigned-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

drivers/hid/surface-hid/surface_hid_core.c

@@ -174,7 +174,7 @@ static int surface_hid_raw_request(struct hid_device *hid, unsigned char reportn
 	return -EIO;
 }
 
-static struct hid_ll_driver surface_hid_ll_driver = {
+static const struct hid_ll_driver surface_hid_ll_driver = {
 	.start       = surface_hid_start,
 	.stop        = surface_hid_stop,
 	.open        = surface_hid_open,