drm/bridge: cdns-dsi: Add support for pre_enable and post_enable control functions.

Add support for pre_enable and post_enable drm bridge control functions.
Making sure that host to be prepared before panel is powered up,
for the panels like TC358762.

Signed-off-by: Jayshri Pawar <jpawar@cadence.com>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220411140606.15654-1-jpawar@cadence.com