Indicate this uses dlmalloc.

Change-Id: Ie7904495b661142d5853070c29ffe49421d7a3cb
diff --git a/BoardConfig.mk b/BoardConfig.mk
index f3dcba4..6782a12 100755
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -26,5 +26,7 @@
 
 TARGET_RECOVERY_FSTAB = device/asus/flo/recovery.fstab
 
+MALLOC_IMPL := dlmalloc
+
 -include vendor/asus/flo/BoardConfigVendor.mk
 include device/asus/flo/BoardConfigCommon.mk