mpc86xx: Use SRR0/1/rfi to enable address translation, not blr

Using a mtmsr/blr means that you have to be executing at the
same virtual address once you enable translation.  This is
unnecessarily restrictive, and is not really how this is
usually done.  Change it to use the more common mtspr SRR0/SRR1
and rfi method.

Signed-off-by: Becky Bruce <becky.bruce@freescale.com>
diff --git a/cpu/mpc86xx/start.S b/cpu/mpc86xx/start.S
index 0d30e91..7e36801 100644
--- a/cpu/mpc86xx/start.S
+++ b/cpu/mpc86xx/start.S
@@ -244,9 +244,15 @@
 	 */
 
 	/* enable address translation */
-	bl	enable_addr_trans
-	sync
+	mfmsr	r5
+	ori	r5, r5, (MSR_IR | MSR_DR)
+	lis	r3,addr_trans_enabled@h
+	ori	r3, r3, addr_trans_enabled@l
+	mtspr	SPRN_SRR0,r3
+	mtspr	SPRN_SRR1,r5
+	rfi
 
+addr_trans_enabled:
 	/* enable and invalidate the data cache */
 /*	bl	l1dcache_enable */
 	bl	dcache_enable
@@ -423,15 +429,6 @@
 	blt tlblp
 	blr
 
-	.globl enable_addr_trans
-enable_addr_trans:
-	/* enable address translation */
-	mfmsr	r5
-	ori	r5, r5, (MSR_IR | MSR_DR)
-	mtmsr	r5
-	isync
-	blr
-
 	.globl disable_addr_trans
 disable_addr_trans:
 	/* disable address translation */