Update my email-address in MAINTAINERS and .mailmap entries to my
kernel.org account.

Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Reviewed-by: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>