drm/radeon/pm: don't allow debugfs/sysfs access when PX card is off (v2)

drm/radeon/pm: don't allow debugfs/sysfs access when PX card is off (v2)

commit 4f2f203976964e267dc477de6648bdb3acd2b74b upstream.

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>
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>