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

MAINTAINERS

@@ -8324,7 +8324,7 @@ W:	https://github.com/o2genum/ideapad-slidebar
 F:	drivers/input/misc/ideapad_slidebar.c
 
 IDT VersaClock 5 CLOCK DRIVER
-M:	Marek Vasut <marek.vasut@gmail.com>
+M:	Luca Ceresoli <luca@lucaceresoli.net>
 S:	Maintained
 F:	drivers/clk/clk-versaclock5.c