[media] v4l: ti-vpe: make vpe driver load scaler coefficients

Make the driver allocate dma buffers to store horizontal and scaler coeffs.
Use the scaler library api to choose and copy scaler coefficients to a
the above buffers based on the scaling ratio. Since the SC block comes after
the de-interlacer, make sure that the source height is doubled if de-interlacer
was used.

These buffers now need to be used by VPDMA to load the coefficients into the
SRAM within SC.

In device_run, add configuration descriptors which have payloads pointing to
the scaler coefficients in memory. Use the members in sc_data handle to prevent
addition of these descriptors if there isn't a need to re-load coefficients into
SC. This comes helps unnecessary re-loading of the coefficients when we switch
back and forth between vpe contexts.

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>