Fix another dereference before null check warning

null tcon is not possible in these paths so
remove confusing null check

Reported by Coverity (CID 728519)
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Jeff Layton <jlayton@samba.org>

fs/cifs/smb2pdu.c

@@ -1632,7 +1632,7 @@ SMB2_flush(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 
 	rc = SendReceive2(xid, ses, iov, 1, &resp_buftype, 0);
 
-	if ((rc != 0) && tcon)
+	if (rc != 0)
 		cifs_stats_fail_inc(tcon, SMB2_FLUSH_HE);
 
 	free_rsp_buf(resp_buftype, iov[0].iov_base);