configs/raspberrypi2: update our defconfig

Update to the latest stable kernel version (4.0.y); build an in-tree DTB.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Floris Bos <bos@je-eigen-domein.nl>
Cc: Pascal de Bruijn <pmjdebruijn@pcode.nl>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

configs/raspberrypi2_defconfig

@@ -7,16 +7,22 @@ BR2_TOOLCHAIN_BUILDROOT_CXX=y
 
 BR2_TARGET_GENERIC_GETTY_PORT="tty1"
 
-# Lock to 3.18 headers as the RPi2 kernel is based off the 3.18 branch
+# Lock to 4.0 headers as the RPi kernel stable tree is
+# based off the 4.0 branch
 BR2_KERNEL_HEADERS_VERSION=y
-BR2_DEFAULT_KERNEL_VERSION="3.18"
-BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_3_18=y
+BR2_DEFAULT_KERNEL_VERSION="4.0.6"
+BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_0=y
 
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_GIT=y
 BR2_LINUX_KERNEL_CUSTOM_REPO_URL="https://github.com/raspberrypi/linux.git"
-BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION="2747cc0bde4ca441691260fae1e34c9ef954ccae"
+BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION="f90f981770e3ac8506dc84c9cd01471faaa0b0c2"
 BR2_LINUX_KERNEL_DEFCONFIG="bcm2709"
-BR2_LINUX_KERNEL_ZIMAGE=y
+BR2_LINUX_KERNEL_ZIMAGE=yo
+
+# Build the DTB from the kernel sources
+BR2_LINUX_KERNEL_DTS_SUPPORT=y
+BR2_LINUX_KERNEL_INTREE_DTS_NAME="bcm2709-rpi-2-b"
 
 BR2_PACKAGE_RPI_FIRMWARE=y
+# BR2_PACKAGE_RPI_FIRMWARE_INSTALL_DTB_OVERLAYS is not set