mailmap: add Marek's other e-mail address and identity without diacritics

Some of my commits were sent with identities
  Marek Behun <marek.behun@nic.cz>
  Marek Behún <marek.behun@nic.cz>
while the correct one is
  Marek Behún <kabel@kernel.org>

Put this into mailmap so that git shortlog prints all my commits under
one identity.

Link: https://lkml.kernel.org/r/20210616113624.19351-2-kabel@kernel.orgSigned-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

.mailmap

@@ -212,6 +212,8 @@ Manivannan Sadhasivam <mani@kernel.org> <manivannanece23@gmail.com>
 Manivannan Sadhasivam <mani@kernel.org> <manivannan.sadhasivam@linaro.org>
 Marcin Nowakowski <marcin.nowakowski@mips.com> <marcin.nowakowski@imgtec.com>
 Marc Zyngier <maz@kernel.org> <marc.zyngier@arm.com>
+Marek Behún <kabel@kernel.org> <marek.behun@nic.cz>
+Marek Behún <kabel@kernel.org> Marek Behun <marek.behun@nic.cz>
 Mark Brown <broonie@sirena.org.uk>
 Mark Starovoytov <mstarovo@pm.me> <mstarovoitov@marvell.com>
 Mark Yao <markyao0591@gmail.com> <mark.yao@rock-chips.com>