staging: vt6656: Remove vnt_interrupt_buffer in_use flag.

mac80211 is the only user of in_use to start it and should
not be true when so.

So internal toggling of this variable is not relevant.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/69585034-4318-4bec-7d9b-f64a167df237@gmail.com


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