mailmap: update Kirill's email

I disconnected from both Virtuozzo and OpenVZ, so this updates my email to
point to my own.  I haven't used @openvz address for patches, so let's
rewrite the line instead of to add a new one.  CC all previous addresses.

Link: https://lkml.kernel.org/r/14ca895b-e745-6ba2-8be8-652feacbc907@ya.ru


Signed-off-by: Kirill Tkhai <tkhai@ya.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>