smb3: remove duplicate error mapping

In status_to_posix_error STATUS_IO_REPARSE_TAG_NOT_HANDLED was mapped
to both -EOPNOTSUPP and also to -EIO but the later one (-EIO) is
ignored. Remove the duplicate.

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