dma: cpp41: enable pm_runtime during init

With enabled pm_runtime in the kernel the device won't work because it
is not "on" during the probe function. This patch enables the device via
pm_runtime on probe so it remains activated.

Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>