drm-kmod sets CONFIG_PM (unclear if for other parts) but LinuxKPI
has no understanding of a dev->power implementation for pm_runtime.h.
The return values based on !CONFIG_PM thus cause problems to drm-kmod.
Return the previous values under CONFIG_PM but leave the TODO logging
as the actual implementation is missing and return values may not be
universally correct (beyond the known drm-kmod use cases).
The following functions having a return value but none sepcific for
CONFIG_PM as (based on drm-kmod master):
pm_runtime_resume only caller ignores the return value
pm_runtime_set_active two callers ignore the return value
pm_runtime_put_autosuspend all callers seem to ignore the return value
pm_runtime_autosuspend 2/3 callers ignore the return value;
3rd is #ifdef __linux__
pm_runtime_suspended 3/4 callers ... do check the return value
but the logic expects the false, which also matches the previous value.
Fixes: 863fe7ae5152 ("LinuxKPI: re-implement pm_runtime.h")
Reported by: markj
MFC after: 3 days