staging: vt6656: vnt_int_start_interrupt remove spin lock.

This formed part of the legacy driver and potentially multi
users.

The driver now has only one user mac80211 remove this lock.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/871a78d4-6d3e-f34b-d0ae-6123803c6faf@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>