MAINTAINERS: Add rpmsg tty driver maintainer

Adding myself as rpmsg tty maintainer and also adding remoteproc
mailing list to inform about changes in the driver.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Link: https://lore.kernel.org/r/20211102123817.19874-1-arnaud.pouliquen@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: arnopo

MAINTAINERS

@@ -16490,6 +16490,12 @@ T:	git git://linuxtv.org/media_tree.git
 F:	Documentation/devicetree/bindings/media/allwinner,sun8i-a83t-de2-rotate.yaml
 F:	drivers/media/platform/sunxi/sun8i-rotate/
 
+RPMSG TTY DRIVER
+M:	Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
+L:	linux-remoteproc@vger.kernel.org
+S:	Maintained
+F:	drivers/tty/rpmsg_tty.c
+
 RTL2830 MEDIA DRIVER
 M:	Antti Palosaari <crope@iki.fi>
 L:	linux-media@vger.kernel.org