MAINTAINERS: update Xinming's email address

I'd like to use this new gmail from now on.

Cc: Ganapathi Bhat <gbhat@marvell.com>
Signed-off-by: Xinming Hu <huxm@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

MAINTAINERS

@@ -8629,7 +8629,7 @@ MARVELL MWIFIEX WIRELESS DRIVER
 M:	Amitkumar Karwar <amitkarwar@gmail.com>
 M:	Nishant Sarmukadam <nishants@marvell.com>
 M:	Ganapathi Bhat <gbhat@marvell.com>
-M:	Xinming Hu <huxm@marvell.com>
+M:	Xinming Hu <huxinming820@gmail.com>
 L:	linux-wireless@vger.kernel.org
 S:	Maintained
 F:	drivers/net/wireless/marvell/mwifiex/