configs: atmel: unify and update defconfig for Xplained boards

Unify and update the defconfig files for Atmel Xplained boards:
- use at91bootstrap as first stage bootloader instead of u-boot spl
- build all dtb variants
- bump to linux4sam_5.2

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
diff --git a/configs/atmel_sama5d3_xplained_defconfig b/configs/atmel_sama5d3_xplained_defconfig
index 665a3d7..197b5ac 100644
--- a/configs/atmel_sama5d3_xplained_defconfig
+++ b/configs/atmel_sama5d3_xplained_defconfig
@@ -2,26 +2,28 @@
 BR2_cortex_a5=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_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_1=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_CUSTOM_REPO_VERSION="linux4sam_5.2"
 BR2_LINUX_KERNEL_DEFCONFIG="sama5"
 BR2_LINUX_KERNEL_ZIMAGE=y
 BR2_LINUX_KERNEL_DTS_SUPPORT=y
-BR2_LINUX_KERNEL_INTREE_DTS_NAME="at91-sama5d3_xplained at91-sama5d3_xplained_pda4 at91-sama5d3_xplained_pda7"
+BR2_LINUX_KERNEL_INTREE_DTS_NAME="at91-sama5d3_xplained at91-sama5d3_xplained_pda4 at91-sama5d3_xplained_pda7 at91-sama5d3_xplained_pda7b"
 BR2_TARGET_ROOTFS_UBIFS=y
 BR2_TARGET_ROOTFS_UBIFS_LEBSIZE=0x1f000
 BR2_TARGET_ROOTFS_UBI=y
 BR2_TARGET_ROOTFS_UBI_SUBSIZE=2048
 BR2_TARGET_AT91BOOTSTRAP3=y
+BR2_TARGET_AT91BOOTSTRAP3_CUSTOM_GIT=y
+BR2_TARGET_AT91BOOTSTRAP3_CUSTOM_REPO_URL="https://github.com/linux4sam/at91bootstrap.git"
+BR2_TARGET_AT91BOOTSTRAP3_CUSTOM_REPO_VERSION="v3.8.4"
 BR2_TARGET_AT91BOOTSTRAP3_DEFCONFIG="sama5d3_xplainednf_uboot"
 BR2_TARGET_UBOOT=y
-BR2_TARGET_UBOOT_BOARDNAME="sama5d3_xplained_nandflash"
+BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y
 BR2_TARGET_UBOOT_CUSTOM_GIT=y
 BR2_TARGET_UBOOT_CUSTOM_REPO_URL="git://github.com/linux4sam/u-boot-at91.git"
-BR2_TARGET_UBOOT_CUSTOM_REPO_VERSION="677f3c2340b72131beebace8e96cac17b9569887"
-BR2_TARGET_UBOOT_SPL=y
+BR2_TARGET_UBOOT_CUSTOM_REPO_VERSION="linux4sam_5.2"
+BR2_TARGET_UBOOT_BOARD_DEFCONFIG="sama5d3_xplained_nandflash"
 BR2_PACKAGE_HOST_SAM_BA=y