drm/i915: split out gem/i915_gem_domain.h from i915_drv.h

We already have the gem/i915_gem_domain.c file.

Cc: Tvrtko Ursulin <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
Signed-off-by: Jani Nikula <[e-mail]>
Acked-by: Tvrtko Ursulin <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/820[e-mail]

drivers/gpu/drm/i915/display/intel_dpt.c

···
  * Copyright © 2021 Intel Corporation
  */
 
+#include "gem/i915_gem_domain.h"
+#include "gt/gen8_ppgtt.h"
+
 #include "i915_drv.h"
 #include "intel_display_types.h"
 #include "intel_dpt.h"
 #include "intel_fb.h"
-#include "gt/gen8_ppgtt.h"
 
 struct i915_dpt {
 	struct i915_address_space vm;

drivers/gpu/drm/i915/display/intel_fb_pin.c

···
  * DOC: display pinning helpers
  */
 
+#include "gem/i915_gem_domain.h"
 #include "gem/i915_gem_object.h"
 
 #include "i915_drv.h"

drivers/gpu/drm/i915/gem/i915_gem_domain.c

···
 
 #include "i915_drv.h"
 #include "i915_gem_clflush.h"
+#include "i915_gem_domain.h"
 #include "i915_gem_gtt.h"
 #include "i915_gem_ioctls.h"
-#include "i915_gem_object.h"
-#include "i915_vma.h"
 #include "i915_gem_lmem.h"
 #include "i915_gem_mman.h"
+#include "i915_gem_object.h"
+#include "i915_vma.h"
 
 static bool gpu_write_needs_clflush(struct drm_i915_gem_object *obj)
 {

drivers/gpu/drm/i915/gem/i915_gem_domain.h

···
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2022 Intel Corporation
+ */
+
+#ifndef __I915_GEM_DOMAIN_H__
+#define __I915_GEM_DOMAIN_H__
+
+struct drm_i915_gem_object;
+enum i915_cache_level;
+
+int i915_gem_object_set_cache_level(struct drm_i915_gem_object *obj,
+				    enum i915_cache_level cache_level);
+
+#endif /* __I915_GEM_DOMAIN_H__ */

drivers/gpu/drm/i915/i915_drv.h

···
 
 int i915_gem_open(struct drm_i915_private *i915, struct drm_file *file);
 
-int i915_gem_object_set_cache_level(struct drm_i915_gem_object *obj,
-				    enum i915_cache_level cache_level);
-
 static inline struct i915_address_space *
 i915_gem_vm_lookup(struct drm_i915_file_private *file_priv, u32 id)
 {