sync: we might be in an unlocked path, so don't just unlock

With out ticket lock, we can't just try to unlock the kernel
and re-lock. Instead, just drop the relock.

XXX: there are more bad things

Author: bluerise

sys/kern/kern_malloc.c

@@ -169,10 +169,6 @@ malloc(size_t size, int type, int flags)
 		if (pool_debug == 2)
 			yield();
 #endif
-		if (!cold && pool_debug) {
-			KERNEL_UNLOCK();
-			KERNEL_LOCK();
-		}
 	}
 
 #ifdef MALLOC_DEBUG