ksmbd: ignore trailing slashes in share paths

Trailing slashes in share paths (like: /home/me/Share/) caused permission
issues with shares for clients on iOS and on Android TV for me,
but otherwise they work fine with plain old Samba.

Cc: stable@vger.kernel.org
Signed-off-by: Nandor Kracser <bonifaido@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>