clocksource/drivers/timer-ti-32k: Add support for initializing directly

Let's allow probing the 32k counter directly based on devicetree data to
prepare for dropping the related legacy platform code. Let's only do this
if the parent node is compatible with ti-sysc to make sure we have the
related devicetree data available.

Let's also show the 32k counter information before registering the
clocksource, now we see it after the clocksource information which is a
bit confusing.

Cc: linux-kernel@vger.kernel.org
Cc: linux-omap@vger.kernel.org
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Lokesh Vutla <lokeshvutla@ti.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Tero Kristo <t-kristo@ti.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200507172330.18679-2-tony@atomide.com