drivers: rtc: Added IRTC Driver Support.

Added NXP IRTC Driver support and binding.
This driver is expected for users needing
Time Date info in their application.
The driver additionally has an alarm mode that
can be enabled to fire an intterupt when the time
and alarm values match.

Signed-off-by: Emilio Benavente <emilio.benavente@nxp.com>