drm/amd/powerplay: bypass fan table setup if no fan connected

If vBIOS noFan bit is set, the fan table parameters in thermal controller
will not get initialized. The driver should avoid to use these uninitialized
parameter to do calculation. Otherwise, it may trigger divide 0 error.

Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org