i915_vma: Rename vma_lookup to i915_vma_lookup

Use i915 prefix to avoid name collision with future vma_lookup() in mm.
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210323134208.3077275-1-Liam.Howlett@Oracle.com

drivers/gpu/drm/i915/i915_vma.c

@@ -230,7 +230,7 @@ vma_create(struct drm_i915_gem_object *obj,
 }
 
 static struct i915_vma *
-vma_lookup(struct drm_i915_gem_object *obj,
+i915_vma_lookup(struct drm_i915_gem_object *obj,
 	   struct i915_address_space *vm,
 	   const struct i915_ggtt_view *view)
 {
@@ -278,7 +278,7 @@ i915_vma_instance(struct drm_i915_gem_object *obj,
 	GEM_BUG_ON(!atomic_read(&vm->open));
 
 	spin_lock(&obj->vma.lock);
-	vma = vma_lookup(obj, vm, view);
+	vma = i915_vma_lookup(obj, vm, view);
 	spin_unlock(&obj->vma.lock);
 
 	/* vma_create() will resolve the race if another creates the vma */