V4L/DVB (11098): v4l2-common: remove incorrect MODULE test

v4l2-common doesn't have to be a module for it to call request_module().
Just remove that test.

Thanks-to: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>