Use arm64 board config for mini_emulator target.

Change-Id: Ib6eade4d8a9895e52a1efe999878c5d08579371a
diff --git a/BoardConfig.mk b/BoardConfig.mk
index 92e7b88..7703b41 100644
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -18,4 +18,4 @@
 # Product-specific compile-time definitions.
 #
 
-include device/generic/armv7-a-neon/BoardConfig.mk
+include device/generic/arm64/BoardConfig.mk