Remove HOST_OS==windows check

With the HOST_CROSS_OS build system change, LOCAL_MULTILIB := first now
behaves the same way.

Change-Id: I03294403e5a106a53d4a0d48b176434221284901
diff --git a/adb/Android.mk b/adb/Android.mk
index c633cee..b228e86 100644
--- a/adb/Android.mk
+++ b/adb/Android.mk
@@ -118,9 +118,7 @@
 LOCAL_STATIC_LIBRARIES := libcrypto_static libbase
 
 LOCAL_C_INCLUDES_windows := development/host/windows/usb/api/
-ifneq ($(HOST_OS),windows)
-    LOCAL_MULTILIB := 64
-endif
+LOCAL_MULTILIB := first
 
 include $(BUILD_HOST_STATIC_LIBRARY)