drm/amd/pm: Clean up errors in navi10_ppt.c

Fix the following errors reported by checkpatch:

ERROR: open brace '{' following function definitions go on the next line
ERROR: space required before the open parenthesis '('
ERROR: space required after that ',' (ctx:VxV)
ERROR: spaces required around that '=' (ctx:VxW)

Signed-off-by: Ran Sun <sunran001@208suo.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>