ksmbd: Move more definitions into the shared area

Move SMB2_SessionSetup, SMB2_Close, SMB2_Read, SMB2_Write and
SMB2_ChangeNotify commands into smbfs_common/smb2pdu.h

Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>