Booting Linux kernel v4.7+ does not work since Linux kernel commit 974f221c
"x86/boot: Move compressed kernel to the end of the decompression buffer".

This patch adds the latest version of the setup_header struct, adding
"init_size" which is needed since this commit referenced above. With this
patch, booting Linux v4.8-rc8 does work again on x86 boards.

Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>