Reverse rockboy patch for 64px-tall displays

[William Shipley via rockbox-dev]

There was a patch to rockboy in 2010 that fixed a problem where the bottom
tile row would be rendered at the top.

Here's the relevant issue from that time:
http://www.rockbox.org/tracker/11745

Note that Stummi openly admits it was a hack, not a true fix.

Sometime in the 6 years since, the root cause was fixed. Currently, rockboy
on the Clip+ and other 64px models shows the top of the gb screen along the
bottom of the display.

I confirmed that reversing this patch fixes the issue on my own Clip+

I've attached a reverse patch file.

--- sys_rockbox.c
+++ sys_rockbox.c
@@ -294,7 +294,7 @@
         scanline-=16;
     else if (fb.mode==2)
         scanline-=8;
-    scanline_remapped = (scanline / 16 + 7) % 8;
+    scanline_remapped = scanline / 16;
     frameb = rb->lcd_framebuffer + scanline_remapped * LCD_WIDTH;
     while (cnt < 160) {
         balance += LCD_WIDTH;