MAINTAINERS: Add Angelo as MediaTek SoC co-maintainer

I am a top reviewer mainly for MediaTek SoC related patches in most
subsystems and I've also been upstreaming both improvements, fixes
and new drivers and devicetrees when required.

The MediaTek scene saw a generous increase in number of patches that
are sent to the lists every week, increasing the amount of required
efforts to maintain the MTK bits overall, and we will possibly see
even more of that.

For this reason, and also because of suggestions and encouragement
coming from the community, I'm stepping up to be a co-maintainer of
MediaTek SoCs support.
Acked-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20230929082009.71843-1-angelogioacchino.delregno@collabora.com
Link: https://lore.kernel.org/r/20231003-mediatek-fixes-v6-7-v1-1-dad7cd62a8ff@collabora.comSigned-off-by: Arnd Bergmann <arnd@arndb.de>

MAINTAINERS

@@ -2327,7 +2327,7 @@ F:	drivers/rtc/rtc-mt7622.c
 
 ARM/Mediatek SoC support
 M:	Matthias Brugger <matthias.bgg@gmail.com>
-R:	AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
+M:	AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
 L:	linux-kernel@vger.kernel.org
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 L:	linux-mediatek@lists.infradead.org (moderated for non-subscribers)