drm/bridge: anx7625: Synchronously run runtime suspend.

Originally when using pm_runtime_put, there's a chance that the runtime
suspend hook will be run after the following anx7625_bridge_mode_set
call, resulting in the display_timing_valid field to be cleared, and the
following power on fail.

Change all pm_runtime_put to pm_runtime_put_sync, so all power off
operations are guaranteed to be done after the call returns.

Fixes: 60487584 ("drm/bridge: anx7625: refactor power control to use runtime PM framework")
Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
Tested-by: Tzung-Bi Shih <tzungbi@google.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/20210520064508.3121211-1-pihsun@chromium.org