drm/i915: Remove i915_gem_object_get_dirty_page()

Last user removed, remove the get_dirty_page convenience function.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200708173748.32734-4-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gem/i915_gem_object.h

@@ -258,10 +258,6 @@ struct page *
 i915_gem_object_get_page(struct drm_i915_gem_object *obj,
 			 unsigned int n);
 
-struct page *
-i915_gem_object_get_dirty_page(struct drm_i915_gem_object *obj,
-			       unsigned int n);
-
 dma_addr_t
 i915_gem_object_get_dma_address_len(struct drm_i915_gem_object *obj,
 				    unsigned long n,

drivers/gpu/drm/i915/gem/i915_gem_pages.c

@@ -548,20 +548,6 @@ i915_gem_object_get_page(struct drm_i915_gem_object *obj, unsigned int n)
 	return nth_page(sg_page(sg), offset);
 }
 
-/* Like i915_gem_object_get_page(), but mark the returned page dirty */
-struct page *
-i915_gem_object_get_dirty_page(struct drm_i915_gem_object *obj,
-			       unsigned int n)
-{
-	struct page *page;
-
-	page = i915_gem_object_get_page(obj, n);
-	if (!obj->mm.dirty)
-		set_page_dirty(page);
-
-	return page;
-}
-
 dma_addr_t
 i915_gem_object_get_dma_address_len(struct drm_i915_gem_object *obj,
 				    unsigned long n,