rtc: pcf2127: add support for PCF2131 RTC

This RTC is very similar in functionality to the PCF2127/29.

Basically it:
  -supports two new control registers at offsets 4 and 5
  -supports a new reset register (not implemented in this driver)
  -supports 4 tamper detection functions instead of 1
  -has no nvmem (like the PCF2129)
  -has two output interrupt pins

Because of that, most of the register addresses are very different,
although they still follow the same layout. For example, the tamper
registers have a different base address, but the offsets are all the same.
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-12-hugo@hugovil.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/Kconfig

@@ -904,9 +904,9 @@ config RTC_DRV_PCF2127
 	select REGMAP_SPI if SPI_MASTER
 	select WATCHDOG_CORE if WATCHDOG
 	help
-	  If you say yes here you get support for the NXP PCF2127/29 RTC
+	  If you say yes here you get support for the NXP PCF2127/29/31 RTC
 	  chips with integrated quartz crystal for industrial applications.
-	  Both chips also have watchdog timer and tamper switch detection
+	  These chips also have watchdog timer and tamper switch detection
 	  features.
 
 	  PCF2127 has an additional feature of 512 bytes battery backed