ksmbd: handle set/get info file for streamed file

ksmbd: handle set/get info file for streamed file

The bug only appears when:
 - windows 11 copies a file that has an alternate data stream
 - streams_xattr is enabled on the share configuration.

Microsoft Edge adds a ZoneIdentifier data stream containing the URL
for files it downloads.

Another way to create a test file:
 - open cmd.exe
 - echo "hello from default data stream" > hello.txt
 - echo "hello again from ads" > hello.txt:ads.txt

If you open the file using notepad, we'll see the first message.
If you run "notepad hello.txt:ads.txt" in cmd.exe, we should see
the second message.

dir /s /r should least all streams for the file.

The truncation happens because the windows 11 client sends
a SetInfo/EndOfFile message on the ADS, but it is instead applied
on the main file, because we don't check fp->stream.

When receiving set/get info file for a stream file, Change to process
requests using stream position and size.
Truncate is unnecessary for stream files, so we skip
set_file_allocation_info and set_end_of_file_info operations.

Reported-by: Marios Makassikis <mmakassikis@freebox.fr>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>