misc/gpsim: Fix fetch

There's a version mismatch in the URL: directory is of a different version than the file so SF doesn't work.

Reported by:	fallout

misc/gpsim/Makefile

@@ -1,7 +1,7 @@
 PORTNAME=	gpsim
 DISTVERSION=	0.32.1
 CATEGORIES=	misc
-MASTER_SITES=	SF
+MASTER_SITES=	https://download.sourceforge.net/project/gpsim/gpsim/0.32.0/ # SF
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	Software simulator for Microchip PIC microcontrollers