boot/uboot: add an upstream URL to Config.in
Add an upstream URL to the help text in Config.in. This
addresses the issue where an incorrect URL is displayed
on the package stats web page.
Signed-off-by: Mark Corbin <mark@dibsco.co.uk>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>