drm/i915/skl: Gen9 Forcewake

Implement common forcewake functions shared by Gen9 features.

v2: Make the focewake_{get,put} functions static (Mika)
    Small coding style fix in the function definition (Damien)

Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Zhe Wang <zhe1.wang@intel.com> (v1)
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com> (v2)
Signed-off-by: Damien Lespiau <damien.lespiau@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 ea22e09..77461ce 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -5833,6 +5833,12 @@
 #define   VLV_GTLC_PW_MEDIA_STATUS_MASK		(1 << 5)
 #define   VLV_GTLC_PW_RENDER_STATUS_MASK	(1 << 7)
 #define  FORCEWAKE_MT				0xa188 /* multi-threaded */
+#define  FORCEWAKE_MEDIA_GEN9			0xa270
+#define  FORCEWAKE_RENDER_GEN9			0xa278
+#define  FORCEWAKE_BLITTER_GEN9			0xa188
+#define  FORCEWAKE_ACK_MEDIA_GEN9		0x0D88
+#define  FORCEWAKE_ACK_RENDER_GEN9		0x0D84
+#define  FORCEWAKE_ACK_BLITTER_GEN9		0x130044
 #define   FORCEWAKE_KERNEL			0x1
 #define   FORCEWAKE_USER			0x2
 #define  FORCEWAKE_MT_ACK			0x130040