MAINTAINERS: Add myself as i8k maintainer

I have a couple of Dell laptops running Linux, so I have a vested
interest to keep this driver supported.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

MAINTAINERS

@@ -2614,7 +2614,7 @@ S:	Maintained
 F:	drivers/platform/x86/dell-laptop.c
 
 DELL LAPTOP SMM DRIVER
-S:	Orphan
+M:	Guenter Roeck <linux@roeck-us.net>
 F:	drivers/char/i8k.c
 F:	include/uapi/linux/i8k.h