Fix a bug in the Fat Stop() function which may return EFI_NOT_FOUND when the controll...

Fix a bug in the Fat Stop() function which may return EFI_NOT_FOUND when the controller handle doesn't support DiskIo2.

Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
(based on FatPkg commit 3454cf4f33cb3b71ebc19705a4d49f1ff3715611)

[jordan.l.justen@intel.com: Use script to relicense to 2-clause BSD]
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Acked-by: Mark Doran <mark.doran@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>