When the PX card is off don't try and access it. Avoid hw access
to the card while it's off (e.g., reading back invalid temperature).

v2: be less strict

bug:
https://bugzilla.kernel.org/show_bug.cgi?id=76321



Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Christian König <christian.koenig@amd.com>