smb: client: extend smb2_compound_op() to accept more commands

Make smb2_compound_op() accept up to MAX_COMPOUND(5) commands to be
sent over a single compounded request.

This will allow next commits to read and write reparse files through a
single roundtrip to the server.
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/client/cifsglob.h

@@ -2238,8 +2238,8 @@ static inline void cifs_sg_set_buf(struct sg_table *sgtable,
 
 struct smb2_compound_vars {
 	struct cifs_open_parms oparms;
-	struct kvec rsp_iov[3];
-	struct smb_rqst rqst[3];
+	struct kvec rsp_iov[MAX_COMPOUND];
+	struct smb_rqst rqst[MAX_COMPOUND];
 	struct kvec open_iov[SMB2_CREATE_IOV_SIZE];
 	struct kvec qi_iov;
 	struct kvec io_iov[SMB2_IOCTL_IOV_SIZE];