ksmbd: allow a filename to contain colons on SMB3.1.1 posix extensions

ksmbd: allow a filename to contain colons on SMB3.1.1 posix extensions

If the client sends SMB2_CREATE_POSIX_CONTEXT to ksmbd, allow the filename
to contain a colon (':'). This requires disabling the support for Alternate
Data Streams (ADS), which are denoted by a colon-separated suffix to the
filename on Windows. This should not be an issue, since this concept is not
known to POSIX anyway and the client has to explicitly request a POSIX
context to get this behavior.

Link: https://lore.kernel.org/all/f9401718e2be2ab22058b45a6817db912784ef61.camel@rx2.rx-server.de/
Signed-off-by: Philipp Kerling <pkerling@casix.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>