MAINTAINERS: Remove Xiaolei Li and mark MTK NFC as orphaned

Xiaolei's address is bouncing, remove him from MAINTAINERS and mark
the driver he was maintaining, Mediatek's, as orphaned.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200510211809.15610-2-miquel.raynal@bootlin.com

MAINTAINERS

@@ -10722,9 +10722,8 @@ F:	Documentation/devicetree/bindings/i2c/i2c-mt7621.txt
 F:	drivers/i2c/busses/i2c-mt7621.c
 
 MEDIATEK NAND CONTROLLER DRIVER
-M:	Xiaolei Li <xiaolei.li@mediatek.com>
 L:	linux-mtd@lists.infradead.org
-S:	Maintained
+S:	Orphan
 F:	Documentation/devicetree/bindings/mtd/mtk-nand.txt
 F:	drivers/mtd/nand/raw/mtk_*