OvmfPkg/VirtioFsDxe: convert FUSE dirent filename to EFI_FILE_INFO

OvmfPkg/VirtioFsDxe: convert FUSE dirent filename to EFI_FILE_INFO

Introduce the VirtioFsFuseDirentPlusToEfiFileInfo() function, for
converting the VIRTIO_FS_FUSE_DIRENTPLUS_RESPONSE filename byte array to
EFI_FILE_INFO.

This new function updates those EFI_FILE_INFO fields (Size, FileName) that
the earlier helper function VirtioFsFuseAttrToEfiFileInfo() does not set.

Both functions together will be able to fill in EFI_FILE_INFO completely,
from FUSE_READDIRPLUS.

Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3097
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20201216211125.19496-35-lersek@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>