MAINTAINERS: Replace my email by one @kernel.org

For the repositories we keep on git.kernel.org replace my email
to be on the same domain for sake of consistency.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20191118135258.37574-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>