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: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

drivers/bluetooth/Makefile

@@ -30,3 +30,5 @@ hci_uart-$(CONFIG_BT_HCIUART_LL)	+= hci_ll.o
 hci_uart-$(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__

net/bluetooth/Makefile

@@ -11,3 +11,5 @@ obj-$(CONFIG_BT_HIDP)	+= hidp/
 bluetooth-y := af_bluetooth.o hci_core.o hci_conn.o hci_event.o mgmt.o \
 	hci_sock.o hci_sysfs.o l2cap_core.o l2cap_sock.o smp.o sco.o lib.o \
 	a2mp.o amp.o
+
+subdir-ccflags-y += -D__CHECK_ENDIAN__