drm/radeon: fix formatting

Preparatory patch: patches to follow will touch a piece of code
that had broken indentication, so fix it before touching it.

Signed-off-by: Ilija Hadzic <ihadzic@research.bell-labs.com>
Reviewed-by: Marek Olšák <maraeo@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>