MAINTAINERS: take over IDT VersaClock 5 clock driver

Marek has been the primary developer of this driver (thanks!). Now as
he is not working on it anymore he suggested I take over maintainership.

Cc: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Link: https://lore.kernel.org/r/20200723074112.3159-3-luca@lucaceresoli.net


Signed-off-by: Stephen Boyd <sboyd@kernel.org>