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>

.mailmap

@@ -221,7 +221,7 @@ Kees Cook <keescook@chromium.org> <kees@ubuntu.com>
 Keith Busch <kbusch@kernel.org> <keith.busch@intel.com>
 Keith Busch <kbusch@kernel.org> <keith.busch@linux.intel.com>
 Kenneth W Chen <kenneth.w.chen@intel.com>
-Kirill Tkhai <kirill.tkhai@openvz.org> <ktkhai@virtuozzo.com>
+Kirill Tkhai <tkhai@ya.ru> <ktkhai@virtuozzo.com>
 Konstantin Khlebnikov <koct9i@gmail.com> <khlebnikov@yandex-team.ru>
 Konstantin Khlebnikov <koct9i@gmail.com> <k.khlebnikov@samsung.com>
 Koushik <raghavendra.koushik@neterion.com>