ksmbd: Replace one-element array with flexible-array member

One-element arrays are deprecated, and we are replacing them with flexible
array members instead. So, replace one-element array with flexible-array
member in struct smb_negotiate_req.

This results in no differences in binary output.

Link: KSPP/linux#79
Link: KSPP/linux#317
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/server/smb_common.h

@@ -200,7 +200,7 @@ struct smb_hdr {
 struct smb_negotiate_req {
 	struct smb_hdr hdr;     /* wct = 0 */
 	__le16 ByteCount;
-	unsigned char DialectsArray[1];
+	unsigned char DialectsArray[];
 } __packed;
 
 struct smb_negotiate_rsp {