Replace MALLOC_IMPL with MALLOC_SVELTE.

Bug: http://b/26390299
Change-Id: I4305750a3d9836a65a9a74014787611c05734ea9
diff --git a/BoardConfig.mk b/BoardConfig.mk
index 275ac6b..01798c2 100644
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -123,7 +123,7 @@
 # let charger mode enter suspend
 BOARD_CHARGER_ENABLE_SUSPEND := true
 
-MALLOC_IMPL := dlmalloc
+MALLOC_SVELTE := true
 
 USE_CLANG_PLATFORM_BUILD := true