added support for the Commander X16 memory layout

c64/kernal/interrupts/fe66.default_brk_handler.s

@@ -9,9 +9,13 @@ default_brk_handler:
 
 	sei // disable IRQs, to be sure they wont interfere
 
+#if CONFIG_PLATFORM_COMMODORE_64
+
 	ldx #$00
 	sta VIC_SCROLX // turn the display off - we want as little screen artifacts as possible
 
+#endif
+
 	cld // make sure this dangerous flag is disabled
 
 	jsr JRESTOR