configs/riotboard: bump kernel to version 4.2.3

Signed-off-by: Nikolay Dimitrov <picmaster@mail.bg>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

configs/riotboard_defconfig

@@ -20,13 +20,13 @@ BR2_TARGET_UBOOT_FORMAT_IMX=y
 
 # kernel headers
 BR2_KERNEL_HEADERS_VERSION=y
-BR2_DEFAULT_KERNEL_VERSION="4.1.3"
-BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_1=y
+BR2_DEFAULT_KERNEL_VERSION="4.2.3"
+BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_2=y
 
 # kernel
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_VERSION=y
-BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.1.3"
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.2.3"
 BR2_LINUX_KERNEL_DEFCONFIG="imx_v6_v7"
 BR2_LINUX_KERNEL_UIMAGE_LOADADDR="0x10008000"
 BR2_LINUX_KERNEL_DTS_SUPPORT=y