commit b1f60b70 upstream.

Must set filter selection as hardcoded coefficients for medium 3x3
filtering, which matches vbios setting for Ironlake.

This fixes display corrupt issue on HP arrandale with new vbios.
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>