Move aarch64-linux-android one directory deeper.

Change-Id: Id39fe4e75d4d3d83b9c6f7a64dad98a41ba9aa47
diff --git a/preamble.mk b/preamble.mk
index 2d243d7..73c5afc 100644
--- a/preamble.mk
+++ b/preamble.mk
@@ -2,7 +2,7 @@
 # common header where useful global vars go.
 
 # Globally useful directories
-TOOLCHAIN := $(ROOTDIR)/toolchain/bin/aarch64-linux-android-
+TOOLCHAIN := $(ROOTDIR)/toolchain/aarch64-linux-android/bin/aarch64-linux-android-
 
 # Kernel directories and options
 KERNEL_SRC_DIR := $(ROOTDIR)/linux-imx