MAINTAINERS: add proc sysctl KUnit test to PROC SYSCTL section

Add entry for the new proc sysctl KUnit test to the PROC SYSCTL section,
and add Iurii as a maintainer.
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

MAINTAINERS

@@ -13132,12 +13132,14 @@ F:	Documentation/filesystems/proc.txt
 PROC SYSCTL
 M:	Luis Chamberlain <mcgrof@kernel.org>
 M:	Kees Cook <keescook@chromium.org>
+M:	Iurii Zaikin <yzaikin@google.com>
 L:	linux-kernel@vger.kernel.org
 L:	linux-fsdevel@vger.kernel.org
 S:	Maintained
 F:	fs/proc/proc_sysctl.c
 F:	include/linux/sysctl.h
 F:	kernel/sysctl.c
+F:	kernel/sysctl-test.c
 F:	tools/testing/selftests/sysctl/
 
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