drm/i915: Adjust watermark register masks

We want to be able to use the masks to decode the register contents
regardless of the hardware generation. So just expand the masks to
cover all available bits, even if those are reserved on some
generations.

v2: Don't extend WM1_LP_SR_MASK so far, for the *future*

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_reg.h

@@ -3251,11 +3251,11 @@
 
 /* define the Watermark register on Ironlake */
 #define WM0_PIPEA_ILK		0x45100
-#define  WM0_PIPE_PLANE_MASK	(0x7f<<16)
+#define  WM0_PIPE_PLANE_MASK	(0xffff<<16)
 #define  WM0_PIPE_PLANE_SHIFT	16
-#define  WM0_PIPE_SPRITE_MASK	(0x3f<<8)
+#define  WM0_PIPE_SPRITE_MASK	(0xff<<8)
 #define  WM0_PIPE_SPRITE_SHIFT	8
-#define  WM0_PIPE_CURSOR_MASK	(0x1f)
+#define  WM0_PIPE_CURSOR_MASK	(0xff)
 
 #define WM0_PIPEB_ILK		0x45104
 #define WM0_PIPEC_IVB		0x45200
@@ -3265,9 +3265,9 @@
 #define  WM1_LP_LATENCY_MASK	(0x7f<<24)
 #define  WM1_LP_FBC_MASK	(0xf<<20)
 #define  WM1_LP_FBC_SHIFT	20
-#define  WM1_LP_SR_MASK		(0x1ff<<8)
+#define  WM1_LP_SR_MASK		(0x7ff<<8)
 #define  WM1_LP_SR_SHIFT	8
-#define  WM1_LP_CURSOR_MASK	(0x3f)
+#define  WM1_LP_CURSOR_MASK	(0xff)
 #define WM2_LP_ILK		0x4510c
 #define  WM2_LP_EN		(1<<31)
 #define WM3_LP_ILK		0x45110