This fixes the following checkpatch warning:

  warning: Prefer 'unsigned int' to bare use of 'unsigned'
Signed-off-by: NBin Meng <bmeng.cn@gmail.com>
Reviewed-by: NChristian Gmeiner <christian.gmeiner@gmail.com>

install_e820_map() has nothing to do with zimage related codes.
Move it to a dedicated place.
Signed-off-by: NBin Meng <bmeng.cn@gmail.com>
Acked-by: NSimon Glass <sjg@chromium.org>