media: verisilicon: Use __set_bit() with local bitmaps

The 'used' and 'new' bitmaps are local to this function, so there is no
need to use atomic access because concurrency can not happen.

Use the non-atomic __set_bit() to save a few cycles.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>