rtc: s32g: add NXP S32G2/S32G3 SoC support

rtc: s32g: add NXP S32G2/S32G3 SoC support

Add a RTC driver for NXP S32G2/S32G3 SoCs.

RTC tracks clock time during system suspend. It can be a wakeup source
for the S32G2/S32G3 SoC based boards.

The RTC module from S32G2/S32G3 is not battery-powered and it is not kept
alive during system reset.

Co-developed-by: Bogdan Hamciuc <bogdan.hamciuc@nxp.com>
Signed-off-by: Bogdan Hamciuc <bogdan.hamciuc@nxp.com>
Co-developed-by: Ghennadi Procopciuc <Ghennadi.Procopciuc@nxp.com>
Signed-off-by: Ghennadi Procopciuc <Ghennadi.Procopciuc@nxp.com>
Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Tested-by: Enric Balletbo i Serra <eballetbo@kernel.org>
Link: https://lore.kernel.org/r/20250403103346.3064895-3-ciprianmarian.costea@oss.nxp.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>