Stop using immap_t on 85xx

In the future the offsets to various blocks may not be in same location.
Move to using CFG_MPC85xx_*_ADDR as the base of the registers
instead of getting it via &immap.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/cpu/mpc85xx/traps.c b/cpu/mpc85xx/traps.c
index efc80c7..2381fb0 100644
--- a/cpu/mpc85xx/traps.c
+++ b/cpu/mpc85xx/traps.c
@@ -288,8 +288,8 @@
 void
 ExtIntException(struct pt_regs *regs)
 {
-	volatile immap_t *immap = (immap_t *)CFG_IMMR;
-	volatile ccsr_pic_t *pic = &immap->im_pic;
+	volatile ccsr_pic_t *pic = (void *)(CFG_MPC85xx_PIC_ADDR);
+
 	uint vect;
 
 #if defined(CONFIG_CMD_KGDB)