drm/i915: pass dev_priv explicitly to CUR_CHICKEN

Avoid the implicit dev_priv local variable use, and pass dev_priv
explicitly to the CUR_CHICKEN register macro.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/0bd1fa8ab346ba2bb40f435136b975b472ad2bc8.1715774156.git.jani.nikula@intel.com


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