fix DIU for small screens

The DIU_DIV register is 8 bit not 5 bit. This prevented large DIV values
so it was not possible to set a slow pixel clock and thus prevented
display on small screens.

Signed-off-by: Kenneth Johansson <kenneth@southpole.se>
Acked-by: John Rigby <jrigby@freescale.com>

board/ads5121/ads5121_diu.c

@@ -57,7 +57,7 @@ void diu_set_pixel_clock(unsigned int pixclock)
 	/* Modify PXCLK in GUTS CLKDVDR */
 	debug("DIU: Current value of CLKDVDR = 0x%08x\n", *clkdvdr);
 	temp = *clkdvdr & 0xFFFFFF00;
-	*clkdvdr = temp | (pixval & 0x1F);
+	*clkdvdr = temp | (pixval & 0xFF);
 	debug("DIU: Modified value of CLKDVDR = 0x%08x\n", *clkdvdr);
 }