media: Remove the legacy v4l2-clk API

The V4L2 temporary clock helper API, was introduced
in late 2012 and, as mentioned in the documentation,
meant to be replaced by the generic clock API,
once the generic clock framework became available
on all relevant architectures.

The generic clock API is a well-established API (since a few
years now). The last few media capture drivers and sensors
using v4l2-clk have been converted to the generic clock framework.

We can now remove the v4l2-clk API.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Acked-by: Petr Cvek <petrcvekcz@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>