Build with Subzero for Android on ARM.

Bug b/37478805

Change-Id: I3a452410d44c0da1cb01c80e3e4fcade221f7304
Reviewed-on: https://swiftshader-review.googlesource.com/9569
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
diff --git a/Android.mk b/Android.mk
index b97a8ba..b4d82e3 100644
--- a/Android.mk
+++ b/Android.mk
@@ -16,6 +16,6 @@
 
 LOCAL_PATH:= $(call my-dir)
 
-ifeq ($(TARGET_ARCH),$(filter $(TARGET_ARCH),x86 x86_64))
+ifeq ($(TARGET_ARCH),$(filter $(TARGET_ARCH),x86 x86_64 arm))
 include $(call all-makefiles-under,$(LOCAL_PATH))
 endif