rtc: Kconfig: add MC34708 to mc13xxx help text

MC34708 is one of the three mfd devices supported by DRV_MC13XXX.
Update Kconfig accordingly.

Signed-off-by: Alexander Kurz <akurz@blala.de>
Link: https://patch.msgid.link/20251011062605.13591-1-akurz@blala.de
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Author: alexanderkurz

drivers/rtc/Kconfig

@@ -1773,7 +1773,7 @@ config RTC_DRV_MC13XXX
 	tristate "Freescale MC13xxx RTC"
 	help
 	  This enables support for the RTCs found on Freescale's PMICs
-	  MC13783 and MC13892.
+	  MC13783, MC13892 and MC34708.
 
 config RTC_DRV_MPC5121
 	tristate "Freescale MPC5121 built-in RTC"