drm/amd/pm: add zero RPM OD setting support for SMU13

Whilst we have support for setting fan curves there is no support for
disabling the zero RPM feature. Since the relevant bits are already
present in the OverDriveTable, hook them up to a sysctl setting so users
can influence this behaviour.

Closes: drm/amd#3489


Reviewed-by: Kenneth Feng <kenneth.feng@amd.com>
Signed-off-by: Wolfgang Müller <wolf@oriole.systems>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>