OvmfPkg/PlatformDxe: Convert Platform.uni to UTF-8

OvmfPkg/PlatformDxe: Convert Platform.uni to UTF-8

This command was used to convert the file:
  iconv -f UTF-16 -t UTF-8 \
    -o OvmfPkg/PlatformDxe/Platform.uni \
    OvmfPkg/PlatformDxe/Platform.uni

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Yingke Liu <yingke.d.liu@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17700 6f19259b-4bc3-4df7-8a09-765794883524