drm/i915: Use intel_ types in intel_{lock,modeset}_all_pipes()

Streamline the code a bit by using intel_ types instead of the
drm_ types.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190701160550.24205-5-ville.syrjala@linux.intel.com


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