rtc: Make mc13783-rtc driver generic

Rename mc13783-rtc so that it can be used for both MC13783 and MC13892 PMICs.

efikamx board, for example, does use a MC13892 PMIC, but the RTC selection is currently made as:

#define CONFIG_RTC_MC13783

,which is not very obvious.

Let the MC13783 and MC13892 RTC be selected by:

#define CONFIG_RTC_MC13XXX

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Stefano Babic <sbabic@denx.de>
diff --git a/include/configs/vision2.h b/include/configs/vision2.h
index bee9e97..2d020ca 100644
--- a/include/configs/vision2.h
+++ b/include/configs/vision2.h
@@ -95,7 +95,7 @@
 #define CONFIG_FSL_PMIC_CLK	2500000
 #define CONFIG_FSL_PMIC_MODE	SPI_MODE_0
 #define CONFIG_FSL_PMIC_BITLEN	32
-#define CONFIG_RTC_MC13783
+#define CONFIG_RTC_MC13XXX
 
 /*
  * MMC Configs