games/bsdgames: atc: Import fix for plane allocation

Where there is only one remaining slot.
This was fixed in NetBSD long time ago.

PR:		268248
Reported by:	m.ne@gmx.net
Approved by:	jockl@pianojockl.org (maintainer, timeout > 2 weeks)
Obtained from:	http://cvsweb.netbsd.org/bsdweb.cgi/src/games/atc/update.c?only_with_tag=MAIN#rev1.22

games/bsdgames/Makefile

@@ -1,6 +1,7 @@
 PORTNAME=	bsdgames
 PORTVERSION=	0.75
 DISTVERSIONPREFIX=	v
+PORTREVISION=	1
 PORTEPOCH=	2
 CATEGORIES=	games
 

games/bsdgames/files/patch-atc_update.c

@@ -0,0 +1,11 @@
+--- atc/update.c.orig	2020-02-26 16:22:47 UTC
++++ atc/update.c
+@@ -284,7 +284,7 @@ next_plane(void)
+ 					break;
+ 				}
+ 	} while (found && last_plane != start_plane);
+-	if (last_plane == start_plane)
++	if (found)
+ 		return (-1);
+ 	return (last_plane);
+ }