V4L/DVB (11204): pvrusb2: Remove old i2c layer; we use v4l2-subdev now

This change removes the old i2c module controlling layer from the
pvrusb2 driver.  This is code that first had appeared in the driver
back in December 2005.  It's history.  Now we use v4l2-subdev.  Please
note also that with this change, the driver will no longer be usable
in kernels older that 2.6.22.

Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>