rtc: use CONFIG_PPC instead of CONFIG_PPC_MERGE

Now that arch/ppc is dead CONFIG_PPC_MERGE is always defined for all
powerpc platforms and we want to get rid of it use CONFIG_PPC instead.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: David Brownell <david-b@pacbell.net>
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>

drivers/rtc/Kconfig

@@ -612,7 +612,7 @@ config RTC_DRV_RS5C313
 
 config RTC_DRV_PPC
        tristate "PowerPC machine dependent RTC support"
-       depends on PPC_MERGE
+       depends on PPC
        help
 	 The PowerPC kernel has machine-specific functions for accessing
 	 the RTC. This exposes that functionality through the generic RTC