Now that all analog-specific code are at em28xx-video, convert
it into an em28xx extension and load it as a separate module.
Reviewed-by: NFrank Schäfer <fschaefer.oss@googlemail.com>
Tested-by: NFrank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>