drm/bridge: it6505: Modified power sequence

Change power sequence to meet it6505 data sheet requirement when boot on.

Signed-off-by: Pin-Yen Lin <treapking@chromium.org>
Signed-off-by: Allen Chen <allen.chen@ite.com.tw>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220715024910.12578-2-allen.chen@ite.com.tw