drm/i915: kill duplicated/unneeded register defines

This looks like a copy-paste remnant from the i810. All the regs
that are actually used are already defined somewhere else in i915_reg.h!
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_reg.h

@@ -709,24 +709,6 @@
 #define ADPA_DPMS_STANDBY	(2<<10)
 #define ADPA_DPMS_OFF		(3<<10)
 
-#define RING_TAIL		0x00
-#define TAIL_ADDR		0x001FFFF8
-#define RING_HEAD		0x04
-#define HEAD_WRAP_COUNT		0xFFE00000
-#define HEAD_WRAP_ONE		0x00200000
-#define HEAD_ADDR		0x001FFFFC
-#define RING_START		0x08
-#define START_ADDR		0xFFFFF000
-#define RING_LEN		0x0C
-#define RING_NR_PAGES		0x001FF000
-#define RING_REPORT_MASK	0x00000006
-#define RING_REPORT_64K		0x00000002
-#define RING_REPORT_128K	0x00000004
-#define RING_NO_REPORT		0x00000000
-#define RING_VALID_MASK		0x00000001
-#define RING_VALID		0x00000001
-#define RING_INVALID		0x00000000
-
 /* Scratch pad debug 0 reg:
  */
 #define   DPLL_FPA01_P1_POST_DIV_MASK_I830	0x001f0000