MAINTAINERS: add HSI subsystem

This adds me as maintainer for the HSI subsystem and
Carlos Chinea (original author) to the CREDITS file.

Signed-off-by: Sebastian Reichel <sre@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 8285ed4..a975b36 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4038,6 +4038,14 @@
 S:	Maintained
 F:	fs/hpfs/
 
+HSI SUBSYSTEM
+M:	Sebastian Reichel <sre@debian.org>
+S:	Maintained
+F:	Documentation/ABI/testing/sysfs-bus-hsi
+F:	drivers/hsi/
+F:	include/linux/hsi/
+F:	include/uapi/linux/hsi/
+
 HSO 3G MODEM DRIVER
 M:	Jan Dumon <j.dumon@option.com>
 W:	http://www.pharscape.org