When registering the rtc device to be used to handle alarm timers,
get_device is used to ensure the device doesn't go away but the module can
still be unloaded. Call try_module_get to ensure the rtc driver will not go
away.
Reported-by: Michal Simek <monstr@monstr.eu> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Tested-by: Michal Simek <michal.simek@xilinx.com> Signed-off-by: Michal Simek <michal.simek@xilinx.com>