drm/i915: s/old_crtc_state/crtc_state/

intel_dp_enable_port() is called during the enable sequence,
so there is nothing old about the passed in crtc state.
Rename it.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200929233449.32323-3-ville.syrjala@linux.intel.com


Reviewed-by: Imre Deak <imre.deak@intel.com>