V4L/DVB: v4l: remove obsolete include/media/v4l2-i2c-drv.h file

The include/media/v4l2-i2c-drv.h header was used to be able to compile drivers
in the v4l-dvb hg repository for legacy kernels (mainly pre-2.6.26) without
creating an #ifdef mess.

The hg repository dropped support for kernels < 2.6.26 so we can remove this
header. All i2c drivers that used it have now been converted to use proper
i2c code. The header was a hack, but it did its job well. So I would call
this an honorable removal. :-)

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>