Fix embedded build

1) Disable dexpreopt if DALVIK_VM_LIB isn't set up by the product.
2) DEX2OAT_TARGET_INSTRUCTION_SET_FEATURES is moved to config.mk,
for it's only decided by target arch.
3) Move Java module input from embedded.mk to base.mk.

Change-Id: Ife70b0cd8cee2e5c92f356c808affa56f494b49a
diff --git a/core/config.mk b/core/config.mk
index 9e30c7d..9b9923a 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -455,6 +455,11 @@
   TARGET_DEFAULT_JAVA_LIBRARIES := core core-junit ext framework framework2
 endif
 
+DEX2OAT_TARGET_INSTRUCTION_SET_FEATURES := default
+ifneq (,$(filter $(TARGET_CPU_VARIANT),cortex-a15 krait))
+DEX2OAT_TARGET_INSTRUCTION_SET_FEATURES := div
+endif
+
 # define clang/llvm tools and global flags
 include $(BUILD_SYSTEM)/clang/config.mk