[media] dib9000: get rid of Dib*Lock macros

The patch replaces Dib*Lock macros with direct calls to mutex functions
as soon as they just make the driver code harder to review
(per request of Mauro).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>