ARM: dts: omap4: Fix functional clocks for ABE DMTimer devices

ARM: dts: omap4: Fix functional clocks for ABE DMTimer devices

The hwmod and clkctrl integration code is currently assigning the
clkctrl clock associated with MODULEMODE as the main functional
clock for nodes that have the ti,hwmods property. This is wrong
for devices that actually use mux or gate clocks as their main
clock and that are not yet converted to the ti-sysc node hierarchy.

The dmtimer clocksource driver cannot use this clock to configure
its parents. All the DMTimer nodes except for those present in the
ABE domain have been converted to the new ti-sysc node hierarchy
style and do not face this issue. The dmtimer consumers got lucky
so far due to the default clock matching the requested parent clock,
and a silent successful return in the omap_dm_timer_set_source()
function. Fix the remaining DMTimer nodes in ABE domain by adding
the actual mux clocks to the DMTimer nodes with the "fck" clock-name.
These clocks are expected to remain even after the nodes have moved
under a ti,sysc parent node.

Signed-off-by: Suman Anna <s-anna@ti.com>