add another mailmap entry for Uwe Kleine-König

I created commit 7971db5a

 on a machine
where I forgot to set user.name and user.email before.  The default
values were not optimal.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>