mailmap: update Mark Yao's email address

Change the previous employers email addresses to the current email
address.

Link: http://lkml.kernel.org/r/20171229121726.31589-1-jeffy.chen@rock-chips.com


Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Acked-by: Martin Kepplinger <martink@posteo.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>