Fix the incorrect DDR clk freq reporting on 8536DS

On 8536DS board, When the DDR clk is set async mode(SW3[6:8] != 111),
The display is still sync mode DDR freq. This patch try to fix
this. The display DDR freq is now the actual freq in both
sync and async mode.

Signed-off-by: Jason Jin <Jason.jin@freescale.com>
diff --git a/cpu/mpc85xx/speed.c b/cpu/mpc85xx/speed.c
index 1cda1e3..485ba20 100644
--- a/cpu/mpc85xx/speed.c
+++ b/cpu/mpc85xx/speed.c
@@ -54,7 +54,8 @@
 
 #ifdef CONFIG_DDR_CLK_FREQ
 	{
-		u32 ddr_ratio = ((gur->porpllsr) & 0x00003e00) >> 9;
+		u32 ddr_ratio = ((gur->porpllsr) & MPC85xx_PORPLLSR_DDR_RATIO)
+			>> MPC85xx_PORPLLSR_DDR_RATIO_SHIFT;
 		if (ddr_ratio != 0x7)
 			sysInfo->freqDDRBus = ddr_ratio * CONFIG_DDR_CLK_FREQ;
 	}