V4L/DVB (7115): Fix bug #9833: regression when compiling V4L without I2C

V4L/DVB (7115): Fix bug #9833: regression when compiling V4L without I2C

Adrian Bunk reported:

> > Commit 8ffbc6559493c64d6194c92d856196fdaeb8a5fb causes the following
> > compile error with CONFIG_VIDEO_DEV=y/m, CONFIG_I2C=n:
> >
> > <--  snip  -->
> >
> > ...
> >   MODPOST 26 modules
> > ERROR: "i2c_attach_client" [drivers/media/video/v4l2-common.ko] undefined!
> > make[2]: *** [__modpost] Error 1
> >
> > <--  snip  -->

...

And what should happen if CONFIG_VIDEO_DEV=y, CONFIG_I2C=m?

CC: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>