Mark getAllocation as deprecated.

Change-Id: If49326ec2cc463e8eacfe9c7680b63ffc53ef3bb
diff --git a/scriptc/rs_allocation.rsh b/scriptc/rs_allocation.rsh
index caf93da..a534088 100644
--- a/scriptc/rs_allocation.rsh
+++ b/scriptc/rs_allocation.rsh
@@ -27,6 +27,9 @@
  * Returns the Allocation for a given pointer.  The pointer should point within
  * a valid allocation.  The results are undefined if the pointer is not from a
  * valid allocation.
+ *
+ * This function is deprecated and will be removed in the SDK from a future
+ * release.
  */
 extern rs_allocation __attribute__((overloadable))
     rsGetAllocation(const void *);