drm/amd/pm: Grant interface access after full init

drm/amd/pm: Grant interface access after full init

Allow access to user interfaces like sysfs/hwmon only after full
initialization of the device. When device is part of XGMI hive and a
reset is required during initialization, the inteface files will be
created as part of minimal device initialization. Full initialization of
the device will be done only after all devices in XGMI hive are probed
and a reset is done together on all.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Asad Kamal <asad.kamal@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>