[arch][arm/arm64] Don't wait for secondary cpus to boot

There are several use cases for this:
- Generic kernel on a system with fewer cpus.
- Systems with two clusters that cannot run concurrently.
- LK as the secure os on a system where secondary cpus do not
  boot until the non-secure os boots.

Change-Id: I17917944c485ff4ac581c159b4abba05471ee5b8

arch/arm/arm/arch.c

@@ -135,11 +135,6 @@ void arch_init(void)
 
 	/* flush the release of the lock, since the secondary cpus are running without cache on */
 	arch_clean_cache_range((addr_t)&arm_boot_cpu_lock, sizeof(arm_boot_cpu_lock));
-
-	/* wait for all of the secondary cpus to boot */
-	while (secondaries_to_init > 0) {
-		__asm__ volatile("wfe");
-	}
 #endif
 
 	//spinlock_test();

arch/arm64/arch.c

@@ -76,11 +76,6 @@ void arch_init(void)
 
     /* flush the release of the lock, since the secondary cpus are running without cache on */
     arch_clean_cache_range((addr_t)&arm_boot_cpu_lock, sizeof(arm_boot_cpu_lock));
-
-    /* wait for all of the secondary cpus to boot */
-    while (secondaries_to_init > 0) {
-        __asm__ volatile("wfe");
-    }
 #endif
 }