configs/mx6cubox: bump U-Boot version

now, the build requires host-swig
which is given by BR2_TARGET_UBOOT_NEEDS_PYLIBFDT

Signed-off-by: Francois Perrad <francois.perrad@gadz.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
1 file changed