buildroot

configs/toradex_apalis_imx6: bump to U-Boot 2016.11 and kernel 4.1.41

Since Toradex V2.7 SDK, U-Boot image has changed from u-boot.imx to
SPL + u-boot.img.

Also fix U-Boot build error with GCC6.

Signed-off-by: Sergio Prado <sergio.prado@e-labworks.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>