faster loading of lines left in render routine

Code/main.asm

@@ -449,6 +449,9 @@ LCDStatInterruptHandler:
 	or a
 	jr z, .exit
 	
+	; move lines left to B
+	ld b, a
+
 	push de
 	push hl
 
@@ -468,8 +471,6 @@ LCDStatInterruptHandler:
 	; load counters
 	ldh a, [TilesLeft]
 	ld c, a
-	ldh a, [LinesLeft]
-	ld b, a
 
 .loop
 	; check we can still render