video: Versatile Express DVI output driver

video: Versatile Express DVI output driver

Versatile Express' DVI video output can be connected to one the three
sources - motherboard's CLCD controller or a video signal generated
by one of the daughterboards.

This driver configures the muxer FPGA so the output displays content
of one of the framebuffers in the system (0 by default, can be changed
by user writing to the "fb" sysfs attribute of the muxfpga device).

It will also set up the display formatter mode and keep it up
to date with mode changes requested by the user (eg. with fbset
tool).

Signed-off-by: Pawel Moll <pawel.moll@arm.com>