drm/i915/phys: unconditionally call release_memory_region

The release method will undo what we did at creation, and so we
shouldn't care if we have pages or not. Fixes a small leak in the
mock_phys selftest.
Signed-off-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200305204258.216302-1-matthew.auld@intel.com

drivers/gpu/drm/i915/gem/i915_gem_phys.c

@@ -194,10 +194,11 @@ int i915_gem_object_attach_phys(struct drm_i915_gem_object *obj, int align)
 	/* Perma-pin (until release) the physical set of pages */
 	__i915_gem_object_pin_pages(obj);
 
-	if (!IS_ERR_OR_NULL(pages)) {
+	if (!IS_ERR_OR_NULL(pages))
 		i915_gem_shmem_ops.put_pages(obj, pages);
-		i915_gem_object_release_memory_region(obj);
-	}
+
+	i915_gem_object_release_memory_region(obj);
+
 	mutex_unlock(&obj->mm.lock);
 	return 0;