video: sunxi: Add mode_valid callback to sunxi_dw_hdmi

Currently driver accepts all resolution which won't work on 4k screens.
Add validation callback which limits acceptable resolutions to 297 MHz.

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
1 file changed