bluetooth: recognize BOARD_BLUETOOTH_USES_HCIATTACH_PROPERTY

Break out top-level define BLUETOOTH_HCIATTACH_USING_PROPERTY under its own
board-level config option.

Change-Id: I51e8d1d4baffe72b861d6f616910452525c8a589
diff --git a/bluedroid/Android.mk b/bluedroid/Android.mk
index c0ccd4f..d372947 100644
--- a/bluedroid/Android.mk
+++ b/bluedroid/Android.mk
@@ -8,6 +8,9 @@
 
 ifeq ($(BOARD_BLUETOOTH_DOES_NOT_USE_RFKILL),true)
   LOCAL_CFLAGS := $(LOCAL_CFLAGS) -DBLUETOOTH_DOES_NOT_USE_RFKILL
+endif
+
+ifeq ($(BOARD_BLUETOOTH_USES_HCIATTACH_PROPERTY),true)
   LOCAL_CFLAGS := $(LOCAL_CFLAGS) -DBLUETOOTH_HCIATTACH_USING_PROPERTY
 endif