Set system PLL vcomax correctly in matroxfb. Discovered by Dirk Uffmann.

drivers/video/matrox/matroxfb_misc.c

@@ -874,7 +874,7 @@ static int parse_pins5(WPMINFO const struct matrox_bios* bd) {
 	mult = bd->pins[4]?8000:6000;
 	
 	MINFO->limits.pixel.vcomax	= (bd->pins[ 38] == 0xFF) ? 600000			: bd->pins[ 38] * mult;
-	MINFO->limits.system.vcomax	= (bd->pins[ 36] == 0xFF) ? MINFO->limits.pixel.vcomax	: bd->pins[ 39] * mult;
+	MINFO->limits.system.vcomax	= (bd->pins[ 36] == 0xFF) ? MINFO->limits.pixel.vcomax	: bd->pins[ 36] * mult;
 	MINFO->limits.video.vcomax	= (bd->pins[ 37] == 0xFF) ? MINFO->limits.system.vcomax	: bd->pins[ 37] * mult;
 	MINFO->limits.pixel.vcomin	= (bd->pins[123] == 0xFF) ? 256000			: bd->pins[123] * mult;
 	MINFO->limits.system.vcomin	= (bd->pins[121] == 0xFF) ? MINFO->limits.pixel.vcomin	: bd->pins[121] * mult;