[media] pwc: precedence bug in pwc_init_controls()

'!' has higher precedence than '&' so we need parenthesis here.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>