MAINTAINERS: Add entry for MediaTek SMI

I am the author of MediaTek SMI driver, and will to maintain
and develop it further.
Add myself to cover these items.
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Link: https://lore.kernel.org/r/20210914113703.31466-14-yong.wu@mediatek.comSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>

MAINTAINERS

@@ -11865,6 +11865,14 @@ M:	Sean Wang <sean.wang@mediatek.com>
 S:	Maintained
 F:	drivers/char/hw_random/mtk-rng.c
 
+MEDIATEK SMI DRIVER
+M:	Yong Wu <yong.wu@mediatek.com>
+L:	linux-mediatek@lists.infradead.org (moderated for non-subscribers)
+S:	Supported
+F:	Documentation/devicetree/bindings/memory-controllers/mediatek,smi*
+F:	drivers/memory/mtk-smi.c
+F:	include/soc/mediatek/smi.h
+
 MEDIATEK SWITCH DRIVER
 M:	Sean Wang <sean.wang@mediatek.com>
 M:	Landen Chao <Landen.Chao@mediatek.com>