spi: rpc-if: Add resume support for RZ/G3E

Merge series from Biju Das <biju.das.jz@bp.renesas.com>:

On RZ/G3E using PSCI, s2ram powers down the SoC. After resume,
reinitialize the hardware for SPI operations.

Also Replace the macro SIMPLE_DEV_PM_OPS->DEFINE_SIMPLE_DEV_PM_OPS macro
and use pm_sleep_ptr(). This lets us drop the check for CONFIG_PM_SLEEP
and __maybe_unused attribute from PM functions.