media: pwc: convert to BIT macro

This converts the driver to using the BIT macro to increase readability

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>