v4l2-dev: add build flag for mmap 32bit

 * some v4l2 drivers need specify mmap MAP_32BIT flags
 * need build with
    $./configure CFLAGS="-DNEED_MAP_32BIT" CXXFLAGS="-DNEED_MAP_32BIT"
 * requirement from Mikhail Tsvetkov

Signed-off-by: Wind Yuan <feng.yuan@intel.com>
1 file changed