pinctrl: renesas: rzg2l: Add suspend/resume support

pinctrl-rzg2l driver is used on RZ/G3S which support deep sleep states
where power to most of the SoC components is turned off.

For this add suspend/resume support. This involves saving and restoring
configured registers along with disabling clock in case there is no pin
configured as wakeup sources.

To save/restore registers 2 caches were allocated: one for GPIO pins and
one for dedicated pins.

On suspend path the pin controller registers are saved and if none of the
pins are configured as wakeup sources the pinctrl clock is disabled.
Otherwise it remains on.

On resume path the configuration is done as follows:
1/ setup PFCs by writing to registers on pin based accesses
2/ setup GPIOs by writing to registers on port based accesses and
   following configuration steps specified in hardware manual
3/ setup dedicated pins by writing to registers on port based accesses
4/ setup interrupts.

Because interrupt signals are routed to IA55 interrupt controller and
IA55 interrupt controller resumes before pin controller, patch restores
also the configured interrupts just after pin settings are restored to
avoid invalid interrupts while resuming.

Signed-off-by: Claudiu Beznea <[email protected]>
Reviewed-by: Geert Uytterhoeven <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Geert Uytterhoeven <[email protected]>