tools/firmware: remove "_PS0/3" Method

tools/firmware: remove "_PS0/3" Method

Do not expose the ACPI power management "_PS0/3" Method to guest
firmware.  According to section 3.4 of the APCI specification 4.0, PCI
device control the device power through its own specification but not
through APCI.

Qemu pushes "_PS0/3" to guest will cause a mess between ACPI PM and
PCI PM as a result of incorrect ACPI table shipped with the guest
BIOS, it may cause a failure of PCI device PM state transition(from
PCI_UNKNOWN to PCI_D0).

Signed-off-by: Xudong Hao <xudong.hao@intel.com>
Signed-off-by: Haitao Shan <haitao.shan@intel.com>
Committed-by: Keir Fraser <keir@xen.org>