MAINTAINERS: add myself to maintain M5441X mmc host driver

Since actively working on Freescale ColdFire M5441X, adding
myself as a maintainer of this driver.

Signed-off-by: Angelo Dureghello <angelo.dureghello@timesys.com>
Link: https://lore.kernel.org/r/20200518191742.1251440-4-angelo.dureghello@timesys.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>