Bluetooth: Enable -D__CHECK_ENDIAN__ for sparse by default

The Bluetooth protocol and hardware is pretty much all little endian
and so when running sparse via "make C=2" for example, enable the
endian checks by default.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
diff --git a/drivers/bluetooth/Makefile b/drivers/bluetooth/Makefile
index 4afae20..9fe8a87 100644
--- a/drivers/bluetooth/Makefile
+++ b/drivers/bluetooth/Makefile
@@ -30,3 +30,5 @@
 hci_uart-$(CONFIG_BT_HCIUART_ATH3K)	+= hci_ath.o
 hci_uart-$(CONFIG_BT_HCIUART_3WIRE)	+= hci_h5.o
 hci_uart-objs				:= $(hci_uart-y)
+
+ccflags-y += -D__CHECK_ENDIAN__