Broken monitoring when CONFIG_PM is disabled in the kernel

Brief summary of the problem:

In 6.13-rc1, AMDGPU monitoring is broken when CONFIG_PM is disabled in the kernel. Many sysfs knobs simply output nothing. For example:

# cd /sys/class/drm/card1/device
# <gpu_busy_percent
# <pp_dpm_sclk
# <pp_od_clk_voltage
# <hwmon/hwmon6/temp1_input

Introduced in agd5f/linux@6e796cb4.