MAINTAINERS: Update my email address to @kernel.org

I will soon lose access to my @arm.com email address, so let's
update the MAINTAINERS file to point to my @kernel.org address,
as well as .mailmap for good measure.

Note that my @arm.com address will still work, but someone else
will be reading whatever is sent there. Don't say you didn't know!

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
diff --git a/.mailmap b/.mailmap
index 0fef932..23cfed2 100644
--- a/.mailmap
+++ b/.mailmap
@@ -132,6 +132,7 @@
 Li Yang <leoyang.li@nxp.com> <leo@zh-kernel.org>
 Li Yang <leoyang.li@nxp.com> <leoli@freescale.com>
 Maciej W. Rozycki <macro@mips.com> <macro@imgtec.com>
+Marc Zyngier <maz@kernel.org> <marc.zyngier@arm.com>
 Marcin Nowakowski <marcin.nowakowski@mips.com> <marcin.nowakowski@imgtec.com>
 Mark Brown <broonie@sirena.org.uk>
 Mark Yao <markyao0591@gmail.com> <mark.yao@rock-chips.com>