Stop using immap_t for guts offset on 85xx

In the future the offsets to various blocks may not be in same location.
Move to using CFG_MPC85xx_GUTS_ADDR as the base of the guts registers
instead of getting it via &immap->im_gur.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/cpu/mpc85xx/speed.c b/cpu/mpc85xx/speed.c
index 12359a2..5c35d4a 100644
--- a/cpu/mpc85xx/speed.c
+++ b/cpu/mpc85xx/speed.c
@@ -35,8 +35,7 @@
 
 void get_sys_info (sys_info_t * sysInfo)
 {
-	volatile immap_t    *immap = (immap_t *)CFG_IMMR;
-	volatile ccsr_gur_t *gur = &immap->im_gur;
+	volatile ccsr_gur_t *gur = (void *)(CFG_MPC85xx_GUTS_ADDR);
 	uint plat_ratio,e500_ratio,half_freqSystemBus;
 
 	plat_ratio = (gur->porpllsr) & 0x0000003e;