Validate that the transform and smb request headers are present
before checking OriginalMessageSize and SessionId fields.

Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Ralph Böhme <slow@samba.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: NTom Talpey <tom@talpey.com>
Acked-by: NHyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: NNamjae Jeon <linkinjeon@kernel.org>
Signed-off-by: NSteve French <stfrench@microsoft.com>