drm/i915: Rename lvds_use_ssc modparam to panel_use_ssc

This modparam affects not only LVDS but also eDP panels. Additionally
with this rename we will keep modparam and i915_params field name in sync.
This patch will unblock us with further improvements around params defs.

Suggested-by: Ville Syrjala <ville.syrjala@intel.com>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Ville Syrjala <ville.syrjala@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170914150805.28376-2-michal.wajdeczko@intel.com