MAINTAINERS: Update maintainer for x86

This adds myself as one of the x86 maintainers.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 9fd9116..f7e6abd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -452,6 +452,7 @@
 
 X86
 M:	Simon Glass <sjg@chromium.org>
+M:	Bin Meng <bmeng.cn@gmail.com>
 S:	Maintained
 T:	git git://git.denx.de/u-boot-x86.git
 F:	arch/x86/