kgdb/kdb/debug_core: Add co-maintainer Daniel Thompson

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>

MAINTAINERS

@@ -7659,6 +7659,7 @@ F:	security/keys/
 
 KGDB / KDB /debug_core
 M:	Jason Wessel <jason.wessel@windriver.com>
+M:	Daniel Thompson <daniel.thompson@linaro.org>
 W:	http://kgdb.wiki.kernel.org/
 L:	kgdb-bugreport@lists.sourceforge.net
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb.git