MAINTAINERS: Specify IRC channel for Renesas ARM32 port

The Renesas ARM ports do have their own IRC channel #renesas-soc (initially
created on Freenode, then moved to Liberta.Chat).  Hopefully, adding it to
this file will attract more people... :-)

Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Link: https://lore.kernel.org/r/2f108f63-0cf7-cc4c-462e-ec63736234cf@omp.ru
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

MAINTAINERS

@@ -2640,6 +2640,7 @@ M:	Magnus Damm <magnus.damm@gmail.com>
 L:	linux-renesas-soc@vger.kernel.org
 S:	Supported
 Q:	http://patchwork.kernel.org/project/linux-renesas-soc/list/
+C:	irc://irc.libera.chat/renesas-soc
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-devel.git next
 F:	Documentation/devicetree/bindings/arm/renesas.yaml
 F:	arch/arm/boot/dts/emev2*