olimex_a20_olinuxino_lime2: bump U-Boot to 2016.05

The patch fixes build by GCC 5 (unsupported by the older U-Boot).

Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
Reported-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

configs/olimex_a20_olinuxino_lime2_defconfig

@@ -25,7 +25,7 @@ BR2_TARGET_ROOTFS_EXT2_4=y
 BR2_TARGET_UBOOT=y
 BR2_TARGET_UBOOT_BOARDNAME="A20-OLinuXino-Lime2"
 BR2_TARGET_UBOOT_CUSTOM_VERSION=y
-BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2015.01"
+BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2016.05"
 BR2_TARGET_UBOOT_SPL=y
 BR2_TARGET_UBOOT_SPL_NAME="u-boot-sunxi-with-spl.bin"
 BR2_PACKAGE_HOST_GENIMAGE=y