Make sure we do not sleep while locks are held. Change the malloc(9)

flags from M_WAITOK to M_NOWAIT. This should not cause any problems
since the calling code appears to properly handle failed allocations.

Discussed with:	kmacy

sys/sun4v/mdesc/mdesc_init.c

@@ -145,7 +145,7 @@ mdesc_buf_free(void *buf, size_t align)
 static void *
 mdesc_meta_alloc(size_t size)
 {
-	return malloc(size, M_MDPROP, M_WAITOK);
+	return malloc(size, M_MDPROP, M_NOWAIT);
 }
 
 static void