rtc-proc: permit the /proc/driver/rtc device to use other devices

To get time information via /proc/driver/rtc, only the first device (rtc0)
is used.  If the rtcN (eg.  rtc1 or rtc2) is used for the system clock,
there is no way to get information of rtcN via /proc/driver/rtc.  With
this patch, the time data can be retrieved from the system clock RTC.

If the RTC_HCTOSYS_DEVICE is not defined, then rtc0 is used by default.

Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
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 fabc99a..a4a805c 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -69,13 +69,15 @@
 	  If unsure, say Y.
 
 config RTC_INTF_PROC
-	boolean "/proc/driver/rtc (procfs for rtc0)"
+	boolean "/proc/driver/rtc (procfs for rtcN)"
 	depends on PROC_FS
 	default RTC_CLASS
 	help
-	  Say yes here if you want to use your first RTC through the proc
-	  interface, /proc/driver/rtc. Other RTCs will not be available
-	  through that API.
+	  Say yes here if you want to use your system clock RTC through
+	  the proc interface, /proc/driver/rtc.
+	  Other RTCs will not be available through that API.
+	  If there is no RTC for the system clock, then the first RTC(rtc0)
+	  is used by default.
 
 	  If unsure, say Y.