Add myself as a maintainer

I am requesting maintainership for the code in the extensions
directories.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: Id2f9e286f7b944afcf09bf5b513a63520098fd5d
diff --git a/MAINTAINERS b/MAINTAINERS
index edd0c08..5bea752 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -43,5 +43,6 @@
 -------------------------
 
 M:  Deepak Kodihalli <dkodihal@linux.vnet.ibm.com> <dkodihal!>
+M:  Matt Spinler <spinler@us.ibm.com> <mspinler!>
 R:  Adriana Kobylak <anoo@us.ibm.com> <anoo!>
 R:  Andrew Geissler <geissonator@yahoo.com> <andrewg!>