drm/i915: s/intel_get_first_crtc/intel_first_crtc/

Since we got rid of the "_get_" from intel_get_crtc_for_pipe()
let's do the same for intel_get_first_crtc() for consistency.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211203112029.1057-3-ville.syrjala@linux.intel.com


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