Update Viresh Kumar's email address

Switch to my kernel.org alias instead of a badly named gmail address,
which I rarely use.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>