Revert "acpi_powerres: acpi_pwr_get_state and getting initial D-state for device"

Setting ACPI D-states is generally broken on FreeBSD and this change
surfaced an issue. So reverting for the time being whilst I write a
proper fix for this.

This reverts commit 02a8fadd2c4dc4b78d6d93d9d8b70e9348a6de6d.

Reported by: glebius, phk
Tested by: glebius
Sponsored by: The FreeBSD Foundation