staging: greybus: hid: Constify lowlevel HID driver

Since commit 52d225346904 ("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 <[e-mail]>
Acked-by: Greg Kroah-Hartman <[e-mail]>
Reviewed-by: Hans de Goede <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Benjamin Tissoires <[e-mail]>

drivers/staging/greybus/hid.c

···
 }
 
 /* HID structure to pass callbacks */
-static struct hid_ll_driver gb_hid_ll_driver = {
+static const struct hid_ll_driver gb_hid_ll_driver = {
 	.parse = gb_hid_parse,
 	.start = gb_hid_start,
 	.stop = gb_hid_stop,