maintainers: Update freedesktop.org IRC channels

Like many free software projects, freedesktop.org issued a non-binding
recommendation for projects to migrate from Freenode to OFTC [1]. As
such, freedesktop.org entries in the MAINTAINERS file are out-of-date as
the respective channels have moved. Update the file to point to the
right network.

v2: Correct typo in commit message pointed out by Lukas and Jonathan.
Add Hector's ack.

v3: Add acks.

[1] https://lists.freedesktop.org/archives/dri-devel/2021-May/307605.html

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Acked-by: Hector Martin <marcan@marcan.st>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210725150007.2818-2-alyssa@rosenzweig.io

MAINTAINERS

@@ -1651,7 +1651,7 @@ L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 S:	Maintained
 W:	https://asahilinux.org
 B:	https://github.com/AsahiLinux/linux/issues
-C:	irc://chat.freenode.net/asahi-dev
+C:	irc://irc.oftc.net/asahi-dev
 T:	git https://github.com/AsahiLinux/linux.git
 F:	Documentation/devicetree/bindings/arm/apple.yaml
 F:	Documentation/devicetree/bindings/interrupt-controller/apple,aic.yaml
@@ -5982,7 +5982,7 @@ M:	Daniel Vetter <daniel@ffwll.ch>
 L:	dri-devel@lists.freedesktop.org
 S:	Maintained
 B:	https://gitlab.freedesktop.org/drm
-C:	irc://chat.freenode.net/dri-devel
+C:	irc://irc.oftc.net/dri-devel
 T:	git git://anongit.freedesktop.org/drm/drm
 F:	Documentation/devicetree/bindings/display/
 F:	Documentation/devicetree/bindings/gpu/
@@ -9137,7 +9137,7 @@ S:	Supported
 W:	https://01.org/linuxgraphics/
 Q:	http://patchwork.freedesktop.org/project/intel-gfx/
 B:	https://gitlab.freedesktop.org/drm/intel/-/wikis/How-to-file-i915-bugs
-C:	irc://chat.freenode.net/intel-gfx
+C:	irc://irc.oftc.net/intel-gfx
 T:	git git://anongit.freedesktop.org/drm-intel
 F:	Documentation/gpu/i915.rst
 F:	drivers/gpu/drm/i915/