linux-phytec-ti

clocksource: timer-ti-dm: Drop bogus omap_dm_timer_of_set_source()

The function omap_dm_timer_of_set_source() was originally added in
commit 31a7448f4fa8a ("ARM: OMAP: dmtimer: Add clock source from DT"),
and is designed to set a clock source from DT using the clocks property
of a timer node. This is a bad design as typically the clocks property
is used to specify the functional clocks for a device, and not its
parents.

The commit 84badc5ec5fc ("ARM: dts: omap4: Move l4 child devices to
probe them with ti-sysc") adds a timer functional clock property to
almost all the timer nodes (except for GPTimers 5, 6, 7, 8 in ABE
domain) on OMAP4 SoCs and this results in an attempt to set the same
functional clock as its parent when a consumer driver attempts to
acquire any of these timers in the omap_dm_timer_prepare() function.
The resulting failure (-EINVAL) also prevents a fallback to the
omap_dm_timer_set_source() function. Fix this by simply dropping
this incorrect logic.

Any DT configuration of clock sources should be achieved using
assigned-clocks and assigned-clock-parents properties provided
by the Common Clock Framework.

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