iwmc3200wifi: check sparse endianness annotations

Add -D__CHECK_ENDIAN__ to driver ccflags so that sparse will
always check endianness by default.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>