arm:caching clean caches before setting up mappings.

Change-Id: I9ff1bb04ea9c0adeb76e5176526448d93bfe29f5

kernel/arch/earm/pre_init.c

@@ -276,6 +276,7 @@ kinfo_t *pre_init(u32_t magic, u32_t ebx)
 	 * to where it should be; but first a 1:1 mapping so
 	 * this code stays where it should be.
 	 */
+	dcache_clean(); /* clean the caches */
 	pg_clear();
 	pg_identity(&kinfo);
 	kinfo.freepde_start = pg_mapkernel();