ARM: omap-device: use SET_NOIRQ_SYSTEM_SLEEP_PM_OPS

Use recently introduced macro SET_NOIRQ_SYSTEM_SLEEP_PM_OPS to
set up PM callbacks. This also fixes missed assignment of
.poweroff_noirq() callback.

Signed-off-by: Grygorii Strashko <Grygorii.Strashko@linaro.org>
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>