HID: bigben: use spinlock to safely schedule workers

Use spinlocks to deal with workers introducing a wrapper
bigben_schedule_work(), and several spinlock checks.
Otherwise, bigben_set_led() may schedule bigben->worker after the
structure has been freed, causing a use-after-free.

Fixes: 4eb1b01d ("HID: hid-bigbenff: fix race condition for scheduled work during removal")
Signed-off-by: Pietro Borrello <borrello@diag.uniroma1.it>
Link: https://lore.kernel.org/r/20230125-hid-unregister-leds-v4-3-7860c5763c38@diag.uniroma1.it


Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>