drm/radeon/kms: Clean up errors in rv6xx_dpm.h

Fix the following errors reported by checkpatch:

ERROR: open brace '{' following struct go on the same line
Signed-off-by: GuoHua Chen <chenguohua_716@163.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/rv6xx_dpm.h

@@ -28,8 +28,7 @@
 #include "r600_dpm.h"
 
 /* Represents a single SCLK step. */
-struct rv6xx_sclk_stepping
-{
+struct rv6xx_sclk_stepping {
     u32 vco_frequency;
     u32 post_divider;
 };