This adds all the OSD configuration plumbing to support the AFBC decoders
path to display of the OSD1 plane.

The Amlogic GXM and G12A AFBC decoders are integrated very differently.

The Amlogic GXM has a direct output path to the OSD1 VIU pixel input,
because the GXM AFBC decoder seem to be a custom IP developed by Amlogic.

On the other side, the Amlogic G12A AFBC decoder seems to be an external
IP that emit pixels on an AXI master hooked to a "Mali Unpack" block
feeding the OSD1 VIU pixel input.
This uses a weird "0x1000000" internal HW physical address on both
sides to transfer the pixels.

For Amlogic GXM, the supported pixel formats are the same as the normal
linear OSD1 mode.

On the other side, Amlogic added support for all AFBC v1.2 formats for
the G12A AFBC integration.

For simplicity, we stick to the already supported formats for now.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191021091509.3864-7-narmstrong@baylibre.com