drm/i915: Skip fence alignemnt check for the CCS plane

drm/i915: Skip fence alignemnt check for the CCS plane

The CCS won't have the same stride as the main surface anyway so trying
to guard against the fence stride not matching the CCS stride is
not sensible. Just skip the fence vs. fb alignment check for the aux
plane.

Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Jason Ekstrand <jason@jlekstrand.net>
Cc: Daniel Stone <daniels@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170824191100.10949-3-ville.syrjala@linux.intel.com
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Fixes: 2e2adb05736c ("drm/i915: Add render decompression support")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>