MAINTAINERS: update maintainer entry for freescale fec driver

Update maintainer entry for freescale fec driver.

Suggested-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -7089,7 +7089,7 @@ S:	Maintained
 F:	drivers/i2c/busses/i2c-cpm.c
 
 FREESCALE IMX / MXC FEC DRIVER
-M:	Fugang Duan <fugang.duan@nxp.com>
+M:	Joakim Zhang <qiangqing.zhang@nxp.com>
 L:	netdev@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/net/fsl-fec.txt