MAINTAINERS: Switch myself to using kernel.org address

I've been running into issues with the linux.dev email
semi-periodically, switching to my kernel.org address while I go figure
out a better home for my inbox.

Signed-off-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/20251107012830.1708225-1-oupton@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: Oliver Upton

.mailmap

@@ -603,7 +603,8 @@ Oleksij Rempel <o.rempel@pengutronix.de>
 Oleksij Rempel <o.rempel@pengutronix.de> <ore@pengutronix.de>
 Oliver Hartkopp <socketcan@hartkopp.net> <oliver.hartkopp@volkswagen.de>
 Oliver Hartkopp <socketcan@hartkopp.net> <oliver@hartkopp.net>
-Oliver Upton <oliver.upton@linux.dev> <oupton@google.com>
+Oliver Upton <oupton@kernel.org> <oupton@google.com>
+Oliver Upton <oupton@kernel.org> <oliver.upton@linux.dev>
 Ondřej Jirman <megi@xff.cz> <megous@megous.com>
 Oza Pawandeep <quic_poza@quicinc.com> <poza@codeaurora.org>
 Pali Rohár <pali@kernel.org> <pali.rohar@gmail.com>

MAINTAINERS

@@ -13642,7 +13642,7 @@ F:	virt/kvm/*
 
 KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)
 M:	Marc Zyngier <maz@kernel.org>
-M:	Oliver Upton <oliver.upton@linux.dev>
+M:	Oliver Upton <oupton@kernel.org>
 R:	Joey Gouly <joey.gouly@arm.com>
 R:	Suzuki K Poulose <suzuki.poulose@arm.com>
 R:	Zenghui Yu <yuzenghui@huawei.com>