smb: client: parse uid, gid, mode and dev from WSL reparse points

Parse the extended attributes from WSL reparse points to correctly
report uid, gid mode and dev from ther instantiated inodes.

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: add support for WSL reparse points

Add support for creating special files via WSL reparse points when
using 'reparse=wsl' mount option. They're faster than NFS reparse
points because they don't require extra roundtrips to figure out what
->d_type a specific dirent is as such information is already stored in
query dir responses and then making getdents() calls faster.

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: move most of reparse point handling code to common file

In preparation to add support for creating special files also via WSL
reparse points in next commits.

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>