smb3: move defines for ioctl protocol header and SMB2 sizes to smbfs_common

The definitions for the ioctl SMB3 request and response as well
as length of various fields defined in the protocol documentation
were duplicated in fs/ksmbd and fs/cifs.  Move these to the common
code in fs/smbfs_common/smb2pdu.h

Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>