staging: omap-thermal: improve conf data handling and initialization

While registering the thermal zone, it is required to have the cooling
devices already setup, so that the .bind callback can succeed.

Due to that, the driver code needs to be reorganized so that we first
setup the cooling devices then the zones. This way we cope with the
right thermal framework initialization sequence.

This patch changes the order of the thermal zone initialization,
so that we create it only when the cooling devices are available.
It also adds some defensive checks for the config data, so that
the callbacks are ready for calls when the data is still not
initialized.

Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>