drm/amdgpu: add missing newline at eof

Representative checkpatch.pl warning

WARNING: adding a line without newline at end of file
 30: FILE: drivers/gpu/drm/amd/pm/swsmu/smu11/vangogh_ppt.h:30:
+#endif

Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>