We use the terms 'distro' to mean extlinux but they are not really the
same. 'Distro' could refer to any method of booting a distribution,
whereas extlinux is a particular method.
Also we sometimes use syslinux, but it is better to use the same term in
all cases.
Rename distro to syslinux and also update bootstd uses of syslinux to use
extlinux instead.
Signed-off-by: Simon Glass <sjg@chromium.org>
The 'bootstd' device provides the central information about U-Boot
standard boot.
Add a uclass for bootstd and the various helpers needed to make it
work. Also add a binding file.
Signed-off-by: Simon Glass <sjg@chromium.org>