OvmfPkg/SmbiosPlatformDxe: split Xen entry point from QEMU entry point

Remove the SmbiosTablePublishEntry() function from "SmbiosPlatformDxe.c".
"SmbiosPlatformDxe.c" becomes hypervisor-agnostic.

Add SmbiosTablePublishEntry() back, simplified for QEMU, to the existent
file "Qemu.c". The GetQemuSmbiosTables() function no longer needs to be
declared in "SmbiosPlatformDxe.h"; "SmbiosPlatformDxe.h" becomes
hypervisor-agnostic.

Add SmbiosTablePublishEntry() back, renamed and simplified for Xen, to the
new, arch-independent file "Xen.c". (The existent Xen-specific C files are
arch-dependent.)

Update both INF files; remove the dependencies that are now superfluous in
each.

Cc: Anthony Perard <anthony.perard@citrix.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Julien Grall <julien@xen.org>
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: <20210526201446.12554-43-lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

OvmfPkg/SmbiosPlatformDxe/XenSmbiosPlatformDxe.inf

@@ -16,7 +16,7 @@
   MODULE_TYPE                    = DXE_DRIVER
   VERSION_STRING                 = 1.0
 
-  ENTRY_POINT                    = SmbiosTablePublishEntry
+  ENTRY_POINT                    = XenSmbiosTablePublishEntry
 
 #
 # The following information is for reference only and not required by the build tools.
@@ -25,9 +25,9 @@
 #
 
 [Sources]
-  Qemu.c
   SmbiosPlatformDxe.c
   SmbiosPlatformDxe.h
+  Xen.c
   XenSmbiosPlatformDxe.h
 
 [Sources.IA32, Sources.X64]
@@ -38,13 +38,12 @@
 
 [Packages]
   MdePkg/MdePkg.dec
+
+[Packages.IA32, Packages.X64]
   OvmfPkg/OvmfPkg.dec
 
 [LibraryClasses]
   DebugLib
-  MemoryAllocationLib
-  PcdLib
-  QemuFwCfgLib
   UefiBootServicesTableLib
   UefiDriverEntryPoint
 
@@ -52,9 +51,6 @@
   BaseLib
   HobLib
 
-[Pcd]
-  gUefiOvmfPkgTokenSpaceGuid.PcdQemuSmbiosValidated
-
 [Protocols]
   gEfiSmbiosProtocolGuid                      # PROTOCOL ALWAYS_CONSUMED