rtc: rename CONFIG_RTC_MXC to CONFIG_RTC_DRV_MXC

In order to keep consistency with other rtc drivers,rename CONFIG_RTC_MXC
to CONFIG_RTC_DRV_MXC.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
[akpm@linux-foundation.org: fix missed arch/arm/configs/imx_v6_v7_defconfig]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 83fb48f..08cbdb9 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1076,7 +1076,7 @@
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-ls1x.
 
-config RTC_MXC
+config RTC_DRV_MXC
 	tristate "Freescale MXC Real Time Clock"
 	depends on ARCH_MXC
 	depends on RTC_CLASS