drm/bridge: lt9611: fix HPD reenablement

The driver will reset the bridge in the atomic_pre_enable(). However
this will also drop the HPD interrupt state. Instead of resetting the
bridge, properly wake it up. This fixes the HPD interrupt delivery after
the disable/enable cycle.

Fixes: 23278bf5 ("drm/bridge: Introduce LT9611 DSI to HDMI bridge")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>