drm/radeon: re-organize the acpi notifier callback

Move it out of the radeon_pm.c and into radeon_acpi.c since
we use it for more than just pm now.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index 8c24718..cb8e94d 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -51,6 +51,7 @@
 
 	if (rdev == NULL)
 		return 0;
+	radeon_acpi_fini(rdev);
 	radeon_modeset_fini(rdev);
 	radeon_device_fini(rdev);
 	kfree(rdev);