smb: Update comments about some reparse point tags

NFS-style reparse points are recognized only by the Windows NFS server 2012
and new. Windows 8 does not contain Windows NFS server, so these reparse
points are not used on Windows 8.

Reparse points with IO_REPARSE_TAG_AF_UNIX tag were primarily introduced for
native Win32 AF_UNIX sockets and later were re-used by also by WSL:
https://devblogs.microsoft.com/commandline/af_unix-comes-to-windows/
https://devblogs.microsoft.com/commandline/windowswsl-interop-with-af_unix/



Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>