drm/edid/firmware: rename drm_load_edid_firmware() to drm_edid_load_firmware()

Follow the usual naming convention by file name.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/d6714ae737d789764bd2bdb6e7c9a5f56c99eef3.1666614699.git.jani.nikula@intel.com