drm/i915: Add PSR2 selective update status registers and bits definitions

This register contains how many blocks was sent in the past selective
updates.
Those registers are not kept set all the times but polling it after flip
can show the values corresponding to the last 8 frames.

v2: Improved macros(Dhinakaran)

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: NDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: NJosé Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190117205548.28378-3-jose.souza@intel.com

drivers/gpu/drm/i915/i915_reg.h

@@ -4272,6 +4272,15 @@ enum {
 #define EDP_PSR2_STATUS_STATE_MASK     (0xf << 28)
 #define EDP_PSR2_STATUS_STATE_SHIFT    28
 
+#define _PSR2_SU_STATUS_0		0x6F914
+#define _PSR2_SU_STATUS_1		0x6F918
+#define _PSR2_SU_STATUS_2		0x6F91C
+#define _PSR2_SU_STATUS(index)		_MMIO(_PICK_EVEN((index), _PSR2_SU_STATUS_0, _PSR2_SU_STATUS_1))
+#define PSR2_SU_STATUS(frame)		(_PSR2_SU_STATUS((frame) / 3))
+#define PSR2_SU_STATUS_SHIFT(frame)	(((frame) % 3) * 10)
+#define PSR2_SU_STATUS_MASK(frame)	(0x3ff << PSR2_SU_STATUS_SHIFT(frame))
+#define PSR2_SU_STATUS_FRAMES		8
+
 /* VGA port control */
 #define ADPA			_MMIO(0x61100)
 #define PCH_ADPA                _MMIO(0xe1100)