85xx: Set HID1[mbdd] on e500v2 rev5.0 or greater

The HID1[MBDD] bit is new on rev5.0 or greater cores and will optimize
the performance of mbar/eieio instructions.

Signed-off-by: Sandeep Gopalpet <sandeep.kumar@freescale.com>
diff --git a/cpu/mpc85xx/release.S b/cpu/mpc85xx/release.S
index 69fce92..0b5b9da 100644
--- a/cpu/mpc85xx/release.S
+++ b/cpu/mpc85xx/release.S
@@ -57,6 +57,13 @@
 
 #ifndef CONFIG_E500MC
 	li	r3,(HID1_ASTME|HID1_ABE)@l	/* Addr streaming & broadcast */
+	mfspr   r0,PVR
+	andi.	r0,r0,0xff
+	cmpwi	r0,0x50@l	/* if we are rev 5.0 or greater set MBDD */
+	blt 1f
+	/* Set MBDD bit also */
+	ori r3, r3, HID1_MBDD@l
+1:
 	mtspr	SPRN_HID1,r3
 #endif