MAINTAINERS: Add myself to write after approval

ChangeLog:

	* MAINTAINERS: Add myself.

MAINTAINERS

@@ -641,6 +641,7 @@ H.J. Lu                         hjl             <hjl.tools@gmail.com>
 Xiong Hu Luo                    -               <luoxhu@gcc.gnu.org>
 Bin Bin Lv                      shlb            <shlb@linux.ibm.com>
 Christophe Lyon                 clyon           <christophe.lyon@arm.com>
+Jin Ma                          majin           <jinma@linux.alibaba.com>
 Jun Ma                          junma           <junma@linux.alibaba.com>
 Andrew MacLeod                  -               <amacleod@redhat.com>
 Luis Machado                    luisgpm         <luisgpm@br.ibm.com>