hal: fix usage of call by reference pointer

The input argument is passed by reference, so only update
the value pointed by the pointer, not the pointer value itself.

CRs-Fixed: 2547766
Change-Id: I34d71afae277de1d93655e1eac845ce533552167
diff --git a/hal/msm8974/platform.c b/hal/msm8974/platform.c
index 38bfeb2..46e02c9 100644
--- a/hal/msm8974/platform.c
+++ b/hal/msm8974/platform.c
@@ -11666,8 +11666,8 @@
     str_parms_get_int(parms, "stream", stream);
     if (*controller < 0 || *controller >= MAX_CONTROLLERS ||
             *stream < 0 || *stream >= MAX_STREAMS_PER_CONTROLLER) {
-        controller = 0;
-        stream = 0;
+        *controller = 0;
+        *stream = 0;
         return -1;
     }
     return 0;