rtc: snvs: Remove unused include of of_device.h

There is nothing in use from of_device.h, remove it.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Link: https://lore.kernel.org/r/1581823666-16944-1-git-send-email-Anson.Huang@nxp.com


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>