MAINTAINERS: Add myself as maintainer for arch/sh (SUPERH)

Both Rich Felker and Yoshinori Sato haven't done any work on arch/sh
for a while. As I have been maintaining Debian's sh4 port since 2014,
I am interested to keep the architecture alive.

Signed-off-by: John Paul Adrian Glaubitz <[email protected]>
Acked-by: Yoshinori Sato <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: glaubitz

MAINTAINERS

@@ -20090,6 +20090,7 @@ F:	drivers/watchdog/sunplus_wdt.c
 SUPERH
 M:	Yoshinori Sato <[email protected]>
 M:	Rich Felker <[email protected]>
+M:	John Paul Adrian Glaubitz <[email protected]>
 L:	[email protected]
 S:	Maintained
 Q:	http://patchwork.kernel.org/project/linux-sh/list/