drm/i915: Wait for LVDS panel power cycle delay on reboot

Just like with eDP let's wait for the power sequencer power
cycle delay before we reboot the machine, as otherwise we
can't guarantee the panel's minimum power cycle delay will
be respected.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201001151640.14590-5-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>