MAINTAINERS: Replace Heikki as maintainer of Intel pinctrl

Heikki has another priorities and no time to maintain Intel pinctrl
driver. As we decided off line I'm going to replace him.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>