drm/i915: Quieten sparse warnings for missing prototypes.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index b6e4b60..e0b7ddc 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4635,8 +4635,8 @@
  * Create a physically contiguous memory object for this object
  * e.g. for cursor + overlay regs
  */
-int i915_gem_init_phys_object(struct drm_device *dev,
-			      int id, int size, int align)
+static int i915_gem_init_phys_object(struct drm_device *dev,
+				     int id, int size, int align)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	struct drm_i915_gem_phys_object *phys_obj;
@@ -4668,7 +4668,7 @@
 	return ret;
 }
 
-void i915_gem_free_phys_object(struct drm_device *dev, int id)
+static void i915_gem_free_phys_object(struct drm_device *dev, int id)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	struct drm_i915_gem_phys_object *phys_obj;