defconfigs/snps_axs_10*: uboot needs dtc

Fixes:
    https://travis-ci.org/buildroot/buildroot-defconfig-testing/jobs/150333758
    https://travis-ci.org/buildroot/buildroot-defconfig-testing/jobs/150333759

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

configs/snps_axs101_defconfig

@@ -23,3 +23,4 @@ BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y
 BR2_TARGET_UBOOT_CUSTOM_VERSION=y
 BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2016.07"
 BR2_TARGET_UBOOT_BOARD_DEFCONFIG="axs101"
+BR2_TARGET_UBOOT_NEEDS_DTC=y

configs/snps_axs103_defconfig

@@ -24,3 +24,4 @@ BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y
 BR2_TARGET_UBOOT_CUSTOM_VERSION=y
 BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2016.07"
 BR2_TARGET_UBOOT_BOARD_DEFCONFIG="axs103"
+BR2_TARGET_UBOOT_NEEDS_DTC=y