configs/atmel_sama5d4ek: remove defconfig

The Atmel sama5d4ek board is no longer sold. Since there is the Xplained
board and we won't maintain anymore the EK board, the defconfig can be
removed. In addition, the defconfig was failing to build with gcc 5.x.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

configs/atmel_sama5d4ek_defconfig

@@ -1,30 +0,0 @@
-BR2_arm=y
-BR2_cortex_a5=y
-BR2_ARM_ENABLE_NEON=y
-BR2_ARM_ENABLE_VFP=y
-BR2_ARM_INSTRUCTIONS_THUMB2=y
-# Linux headers same as kernel, a 3.18 series
-BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_3_18=y
-BR2_LINUX_KERNEL=y
-BR2_LINUX_KERNEL_CUSTOM_GIT=y
-BR2_LINUX_KERNEL_CUSTOM_REPO_URL="https://github.com/linux4sam/linux-at91.git"
-BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION="03329ca4cf6b94acc5c65b59b2d1f90fdeee0887"
-BR2_LINUX_KERNEL_DEFCONFIG="sama5"
-BR2_LINUX_KERNEL_DTS_SUPPORT=y
-BR2_LINUX_KERNEL_INTREE_DTS_NAME="at91-sama5d4ek"
-BR2_TARGET_ROOTFS_UBIFS=y
-BR2_TARGET_ROOTFS_UBIFS_LEBSIZE=0x3e000
-BR2_TARGET_ROOTFS_UBIFS_MINIOSIZE=0x1000
-BR2_TARGET_ROOTFS_UBIFS_MAXLEBCNT=2082
-BR2_TARGET_ROOTFS_UBI=y
-BR2_TARGET_ROOTFS_UBI_PEBSIZE=0x40000
-BR2_TARGET_ROOTFS_UBI_SUBSIZE=0
-BR2_TARGET_AT91BOOTSTRAP3=y
-BR2_TARGET_AT91BOOTSTRAP3_DEFCONFIG="sama5d4eknf_uboot_secure"
-BR2_TARGET_UBOOT=y
-BR2_TARGET_UBOOT_BOARDNAME="sama5d4ek_nandflash"
-BR2_TARGET_UBOOT_CUSTOM_GIT=y
-BR2_TARGET_UBOOT_CUSTOM_REPO_URL="https://github.com/linux4sam/u-boot-at91.git"
-BR2_TARGET_UBOOT_CUSTOM_REPO_VERSION="677f3c2340b72131beebace8e96cac17b9569887"
-BR2_TARGET_UBOOT_SPL=y
-BR2_PACKAGE_HOST_SAM_BA=y