wl1251: enable sparse endianess check by default

Following the good example of the Intel (and more recently Atheros)
drivers, enable endianess check by default when running sparse.
Signed-off-by: NLuciano Coelho <coelho@ti.com>

drivers/net/wireless/wl1251/Makefile

@@ -6,3 +6,5 @@ wl1251_sdio-objs	+= sdio.o
 obj-$(CONFIG_WL1251)		+= wl1251.o
 obj-$(CONFIG_WL1251_SPI)	+= wl1251_spi.o
 obj-$(CONFIG_WL1251_SDIO)	+= wl1251_sdio.o
+
+ccflags-y += -D__CHECK_ENDIAN__