OvmfPkg: switch IA32, IA32X64, X64 to the fw_cfg-only ACPI platform driver

OvmfPkg: switch IA32, IA32X64, X64 to the fw_cfg-only ACPI platform driver

Switch the historical OvmfPkg* platforms from the AcpiPlatformDxe driver
to the QemuFwCfgAcpiPlatformDxe driver. (The latter is used by the
ArmVirtQemu* platforms as well.)

The change effectively replaces the following call tree:

  InstallAcpiTables                [AcpiPlatform.c]

    XenDetected                    [XenPlatformLib] *
    InstallXenTables               [Xen.c]          *
      GetXenAcpiRsdp               [Xen.c]          *

    InstallQemuFwCfgTables         [QemuFwCfgAcpi.c]
      ...

    InstallOvmfFvTables            [AcpiPlatform.c] *
      QemuDetected                 [Qemu.c]         *
      LocateFvInstanceWithTables   [AcpiPlatform.c] *
        QemuInstallAcpiTable       [Qemu.c]         *
          QemuInstallAcpiMadtTable [Qemu.c]         *
            CountBits16            [Qemu.c]         *
          QemuInstallAcpiSsdtTable [Qemu.c]         *
            GetSuspendStates       [Qemu.c]         *
            PopulateFwData         [Qemu.c]         *

with the one below:

  InstallAcpiTables        [QemuFwCfgAcpiPlatform.c]
    InstallQemuFwCfgTables [QemuFwCfgAcpi.c]
      ...

eliminating the sub-trees highlighted with "*".

There are two consequences:

(1) Xen compatibility is removed from the ACPI platform driver of the
   historical OvmfPkg* platforms.

(2) The ACPI tables that are statically built into OVMF (via
    "OvmfPkg/AcpiTables/AcpiTables.inf") are never installed. In
    particular, OVMF's own runtime preparation of the MADT and SSDT is
    eliminated.

Because of (2), remove the "OvmfPkg/AcpiTables/AcpiTables.inf" module as
well -- and then the ACPITABLE build rule too.

Note that (2) only removes effectively dead code; the QEMU ACPI
linker-loader has taken priority since QEMU 1.7.1 (2014). References:

- https://wiki.qemu.org/Planning/1.7
- https://wiki.qemu.org/Features/ACPITableGeneration
- edk2 commit 96bbdbc85693 ("OvmfPkg: AcpiPlatformDxe: download ACPI
                            tables from QEMU", 2014-03-31)
- edk2 commit 387536e472aa ("OvmfPkg: AcpiPlatformDxe: implement QEMU's
                            full ACPI table loader interface", 2014-09-22)

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2122
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20210526201446.12554-4-lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>