Makefile: add update-defconfig target

For symmetry with the Kconfig-based packages offering comprehensive
targets like linux-update-defconfig, barebox-update-defconfig and so
on, add a new top level update-defconfig target to run savedefconfig.

Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
Reviewed-by: Titouan Christophe <titouan.christophe@railnova.eu>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
1 file changed