acpi: drop build_piix4_pm()

acpi: drop build_piix4_pm()

The _SB.PCI0.PX13.P13C opregion (holds isa device enable bits)
is not used any more, remove it from DSDT.

piix4 DSDT changes:

     Scope (_SB.PCI0)
     {
-        Device (PX13)
-        {
-            Name (_ADR, 0x00010003)  // _ADR: Address
-            OperationRegion (P13C, PCI_Config, Zero, 0xFF)
-        }
-    }
-
-    Scope (_SB.PCI0)
-    {
         Device (ISA)
         {
             Name (_ADR, 0x00010000)  // _ADR: Address
             OperationRegion (P40C, PCI_Config, 0x60, 0x04)
         }
     }

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Igor Mammedow <imammedo@redhat.com>
Message-Id: <20200619091905.21676-11-kraxel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>