EFI_FILE_PROTOCOL spec conformance bug fix.

EFI_FILE_PROTOCOL spec conformance bug fix.

1. Write() should return Unsupported instead of WriteProtected when operating above a directory in read-only media.
2. SetInfo() should return Unsupported instead of WriteProtected when operating above a directory using a undefined GUID in read-only media.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Eric Jin <eric.jin@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
(based on FatPkg commit 8ff136aaa3fff82d81514fd3091961ec4a63c873)

[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>