[media] v4l: ti-vpe: create a scaler block library

VPE and VIP IPs in DAR7x contain a scaler(SC) sub block. Create a library which
will perform scaler block related configurations and hold SC register
definitions. The functions provided by this library will be called by the vpe
and vip drivers using a sc_data handle.

The vpe_dev holds the sc_data handle. The handle represents an instance of the
SC hardware, and the vpe driver uses it to access the scaler register offsets
or helper functions to configure these registers.

We move the SC register definitions to sc.h so that they aren't specific to
VPE anymore. The register offsets are now relative to the sub-block, and not the
VPE IP as a whole. In order for VPDMA to configure registers, it requires it's
offset from the top level VPE module. A macro called GET_OFFSET_TOP is added to
return the offset of the register relative to the VPE IP.

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>