[media] v4l: ti-vpe: Add helper to perform color conversion

The CSC block can be used for color space conversion between YUV and RGB
formats.

It is configurable via a programmable set of coefficients. Add functionality to
choose the appropriate CSC coefficients and program them in the CSC registers.
We take the source and destination colorspace formats as the arguments, and
choose the coefficient table accordingly.

YUV to RGB coefficients are provided for standard and high definition
colorspaces. The coefficients can also be limited or full range. For now, only
full range coefficients are chosen. We would need some sort of control ioctl for
the user to specify the range needed. Not sure if there is a generic control
ioctl for this already?

Signed-off-by: Archit Taneja <archit@ti.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>