drm/i915: Disable M2 frac division for integer case

v2 : Handle M2 frac division for both M2 frac and int cases

v3 : Addressed Ville's review comments. Cleared the old bits for RMW

v4 : Fix feedfwd gain (Ville)

Signed-off-by: Vijay Purushothaman <vijay.a.purushothaman@linux.intel.com>
Reviewed-by: Ville Syrjala <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index f700922..17b662f 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1029,6 +1029,7 @@
 #define  DPIO_CHV_FIRST_MOD		(0 << 8)
 #define  DPIO_CHV_SECOND_MOD		(1 << 8)
 #define  DPIO_CHV_FEEDFWD_GAIN_SHIFT	0
+#define  DPIO_CHV_FEEDFWD_GAIN_MASK		(0xF << 0)
 #define CHV_PLL_DW3(ch) _PIPE(ch, _CHV_PLL_DW3_CH0, _CHV_PLL_DW3_CH1)
 
 #define _CHV_PLL_DW6_CH0		0x8018