MAINTAINERS: Update info for William Breathitt Gray

A new job position bestowed a new email address and Counter subsystem
git tree for me.

Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Link: https://lore.kernel.org/r/694c2da1a01d1a3065239bf2c060018cb3308c34.1657813472.git.william.gray@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>