drm/i915: Move the lspcon resume from .reset() to intel_dp_sink_dpms()

drm/i915: Move the lspcon resume from .reset() to intel_dp_sink_dpms()

Rather that try to trick LSPCON back into PCON mode from the .reset()
hook let's just do that as a regular part of the normal modeset
sequence, which is going to take care of the system resume case. During
a normal modeset this should normally be a nop as the mode should have
already been switched by .detect().

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201016194800.25581-1-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>