drm/i915: Clean up arguments to nv12/scaler w/a funcs

Don't pass the redundant dev_priv to needs_nv12_wa() and
needs_scalerclk_wa().

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191127190556.1574-2-ville.syrjala@linux.intel.com


Reviewed-by: José Roberto de Souza <jose.souza@intel.com>