drm/i915: Use a mask when applying WaProgramL3SqcReg1Default

drm/i915: Use a mask when applying WaProgramL3SqcReg1Default

Otherwise we are blasting other bits in GEN8_L3SQCREG1 that might be important
(although we probably aren't at the moment because 0 seems to be the default
for all the other bits).

v2: Extra parentheses (Michel)

Fixes: 050fc46 ("drm/i915:bxt: implement WaProgramL3SqcReg1DefaultForPerf")
Fixes: 450174f ("drm/i915/chv: Tune L3 SQC credits based on actual latencies")
Signed-off-by: Oscar Mateo <[email protected]>
Cc: Chris Wilson <[email protected]>
Cc: Mika Kuoppala <[email protected]>
Cc: Ville Syrjälä <[email protected]>
Cc: Imre Deak <[email protected]>
Reviewed-by: Michel Thierry <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Signed-off-by: Chris Wilson <[email protected]>