drm/radeon: Clean up errors in trinity_dpm.c

Fix the following errors reported by checkpatch:

ERROR: that open brace { should be on the previous line
ERROR: space prohibited before that ',' (ctx:WxW)
ERROR: need consistent spacing around '-' (ctx:WxV)

Signed-off-by: GuoHua Chen <chenguohua_716@163.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>