Add slot number to forEach hal.

Change-Id: I0f2992d5f4128422d07f897b335c219cc7f1d02c
diff --git a/rs_hal.h b/rs_hal.h
index 928dca5..6a4537b 100644
--- a/rs_hal.h
+++ b/rs_hal.h
@@ -70,6 +70,7 @@
         int (*invokeRoot)(const Context *rsc, Script *s);
         void (*invokeForEach)(const Context *rsc,
                               Script *s,
+                              uint32_t slot,
                               const Allocation * ain,
                               Allocation * aout,
                               const void * usr,