Gen3+ is 13 bits (12:0), and on gen2 only 12 (11:0). For both the high
bits are marked reserved, read-only so continue to mask them. Bit 31
is not reserved and has a meaning.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>