Blank screen

[BroderTuck70]

Been a while since I looked at this last, but I seem to remember that I had to
revert this change from the "abandon writeback, add overscan" commit to get output
with my device and TV:

display.c
@@ -13,7 +13,7 @@ void display_clocks_init() {
DE_CLK = (1<<31) | (1<<24); // Enable DE clock, set source to PLL_DE
HDMI_CLK = (1<<31); // Enable HDMI clk (use PLL3)
HDMI_SLOW_CLK = (1<<31); // Enable HDMI slow clk

• TCON0_CLK = (1<<31) | 1; // Enable TCON0 clk, divide by 2

• TCON0_CLK = (1<<31) | 3; // Enable TCON0 clk, divide by 4
  }