OvmfPkg: exclude 8254TimerDxe

In the original three OVMF platforms, CSM_ENABLE selects the legacy timer
driver; exclude it. Instead, include LocalApicTimerDxe unconditionally
(which in turn consumes PcdFSBClock).

Background: commits c37cbc030d ("OvmfPkg: Switch timer in build time for
OvmfPkg", 2022-04-02) and 07c0c2eb0a ("OvmfPkg: fix PcdFSBClock",
2022-05-25).

Regression test: verified that the BDS progress bar still advanced at
normal speed in each platform.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=4588
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20231110235820.644381-32-lersek@redhat.com>
Reviewed-by: Jiewen Yao <Jiewen.yao@intel.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Corvin Köhne <corvink@FreeBSD.org>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>

OvmfPkg/OvmfPkgX64.dsc

@@ -702,9 +702,7 @@
   # Set ConfidentialComputing defaults
   gEfiMdePkgTokenSpaceGuid.PcdConfidentialComputingGuestAttr|0
 
-!if $(CSM_ENABLE) == FALSE
   gEfiMdePkgTokenSpaceGuid.PcdFSBClock|1000000000
-!endif
 
 [PcdsDynamicHii]
 !include OvmfPkg/Include/Dsc/OvmfTpmPcdsHii.dsc.inc
@@ -840,10 +838,8 @@
 
 !ifdef $(CSM_ENABLE)
   OvmfPkg/8259InterruptControllerDxe/8259.inf
-  OvmfPkg/8254TimerDxe/8254Timer.inf
-!else
-  OvmfPkg/LocalApicTimerDxe/LocalApicTimerDxe.inf
 !endif
+  OvmfPkg/LocalApicTimerDxe/LocalApicTimerDxe.inf
   OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf
   OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.inf
   MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf {