drm/radeon/dpm: Clean up errors in sumo_dpm.c

Fix the following errors reported by checkpatch:

ERROR: that open brace { should be on the previous line
ERROR: space prohibited before that close parenthesis ')'
ERROR: spaces required around that '?' (ctx:VxW)

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