media: nuvoton: Add driver for NPCM video capture and encoding engine

Add driver for Video Capture/Differentiation Engine (VCD) and Encoding
Compression Engine (ECE) present on Nuvoton NPCM SoCs. As described in
the datasheet NPCM750D_DS_Rev_1.0, the VCD can capture frames from
digital video input and compare two frames in memory, and then the ECE
can compress the frame data into HEXTILE format. This driver implements
V4L2 interfaces and provides user controls to support KVM feature, also
tested with VNC Viewer ver.6.22.826 and openbmc/obmc-ikvm.

Signed-off-by: Marvin Lin <milkfafa@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>