Add Zhuikui into maintainers list

As Zhuikui continuously contributes to smbios,
add her as maintainer.

Change-Id: I8d20373b708adc11ba44d6bbae611b63e1bc143a
Signed-off-by: Kuiying Wang <kuiying.wang@intel.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 9b975c6..d669fec 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -44,3 +44,4 @@
 
 M:  Chen Yugang <yugang.chen@linux.intel.com> <ygangch!>
 M:  Kuiying Wang <kuiying.wang@intel.com> <kuiyingw!> 
+M:  Zhikui Ren <zhikui.ren@intel.com> <zhikuir!>