drm/i915: Pass dev_priv to skl_needs_memory_bw_wa()

skl_needs_memory_bw_wa() doesn't look at the passed in state at all.
Possibly it should, but for now let's make life simpler by just
passing in dev_priv.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181221171436.8218-7-ville.syrjala@linux.intel.com


Reviewed-by: Matt Roper <matthew.d.roper@intel.com>