board: add support for Minnowboard MAX

Very similar to the older Minnowboard, except that it works with mainline
Linux, uses 64bit firmware and a realtek NIC needing firmware.

The Linux configuration is based on the configuration fragment on elinux:
http://elinux.org/Minnowboard:MinnowMaxLinuxKernel

Many thanks to Circuitco for sponsoring a board.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

configs/minnowboard_max_defconfig

@@ -0,0 +1,27 @@
+# Architecture
+BR2_x86_64=y
+BR2_x86_atom=y
+
+# Misc
+BR2_TARGET_GENERIC_GETTY_PORT="ttyS0"
+BR2_ROOTFS_POST_BUILD_SCRIPT="board/minnowboard-max/post-build.sh"
+
+# Lock to 3.17 headers to avoid breaking with newer kernels
+BR2_KERNEL_HEADERS_VERSION=y
+BR2_DEFAULT_KERNEL_VERSION="3.17.2"
+BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_3_17=y
+
+# Needed for ethernet
+BR2_PACKAGE_LINUX_FIRMWARE=y
+BR2_PACKAGE_LINUX_FIRMWARE_RTL_8169=y
+
+# Linux kernel
+BR2_LINUX_KERNEL=y
+BR2_LINUX_KERNEL_CUSTOM_VERSION=y
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="3.17.2"
+BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
+BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/minnowboard-max/linux-3.17.config"
+
+# Bootloader
+BR2_TARGET_GRUB2=y
+BR2_TARGET_GRUB2_X86_64_EFI=y