ARM: dts: Configure also interconnect clocks for am4 system timer

We now manage clocksource and clockevent clocks directly with
timer-ti-dm-systimer. In order to use genpd with prm_omap,
GENPD_FLAG_PM_CLK and simple-pm-bus, we need to keep the system
timer related interconnect clocks enabled until clocksource suspend
is done.

Signed-off-by: Tony Lindgren <tony@atomide.com>