powerpc/mpc85xx: Clear L1 D-cache lock

dcbi instruction has been used to clear D-cache lock. However, the cache
lock is persistent for e6500 core. Use dcblc to clear the lock explicitly.

Signed-off-by: York Sun <yorksun@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>

arch/powerpc/cpu/mpc85xx/start.S

@@ -1906,6 +1906,7 @@ unlock_ram_in_cache:
 	slwi	r4,r4,(10 - 1 - L1_CACHE_SHIFT)
 	mtctr	r4
 1:	dcbi	r0,r3
+	dcblc	r0,r3
 	addi	r3,r3,CONFIG_SYS_CACHELINE_SIZE
 	bdnz	1b
 	sync