OvmfPkg: SmbiosVersionLib: recognize SMBIOS 3.x entry point

Also set the DocRev field the way QEMU exposes it, because
MdeModulePkg/Universal/SmbiosDxe lets us control that field too.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Wei Huang <wei@redhat.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Gabriel L. Somlo <somlo@cmu.edu>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18182 6f19259b-4bc3-4df7-8a09-765794883524