MAINTAINERS: remove me from sysctl

Joel has been doing a great job at sysctl maintenance, and I've tried
to use my time to help with other efforts, so just remove myself
from sysctl maintenance list.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Joel Granados <joel.granados@kernel.org>

Author: mcgrof

MAINTAINERS

@@ -18580,7 +18580,6 @@ F:	include/linux/proc_fs.h
 F:	tools/testing/selftests/proc/
 
 PROC SYSCTL
-M:	Luis Chamberlain <mcgrof@kernel.org>
 M:	Kees Cook <kees@kernel.org>
 M:	Joel Granados <joel.granados@kernel.org>
 L:	linux-kernel@vger.kernel.org