MAINTAINERS: add myself

[Jiufu Guo]

2019-01-21  Jiufu Guo  <guojiufu@linux.ibm.com>

	* MAINTAINERS (Write After Approval): Add myself.

Index: MAINTAINERS
===================================================================
--- MAINTAINERS	(revision 268134)
+++ MAINTAINERS	(working copy)
@@ -400,6 +400,7 @@ Matthew Gretton-Dann				<matthew.gretton-dann@arm.
 Yury Gribov					<tetra2005@gmail.com>
 Jon Grimm					<jgrimm2@us.ibm.com>
 Laurent Guerby					<laurent@guerby.net>
+Jiufu Guo					<guojiufu@linux.ibm.com>
 Xuepeng Guo					<terry.xpguo@gmail.com>
 Wei Guozhi					<carrot@google.com>
 Mostafa Hagog					<hagog@gcc.gnu.org>