drm/bridge/synopsys: dsi: add support for non-continuous HS clock

drm/bridge/synopsys: dsi: add support for non-continuous HS clock

Current code enables the HS clock when video mode is started or to
send out a HS command, and disables the HS clock to send out a LP
command. This is not what DSI spec specify.

Enable HS clock either in command and in video mode.
Set automatic HS clock management for panels and devices that
support non-continuous HS clock.

Signed-off-by: Antonio Borneo <[email protected]>
Tested-by: Philippe Cornu <[email protected]>
Reviewed-by: Philippe Cornu <[email protected]>
Acked-by: Neil Armstrong <[email protected]>
Signed-off-by: Neil Armstrong <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]