sparc: time: Replace update_persistent_clock() with CONFIG_RTC_SYSTOHC

On Sparc systems, update_persistent_clock() uses RTC drivers to do
the job, it makes more sense to hand it over to CONFIG_RTC_SYSTOHC.

In the long run, all the update_persistent_clock() should migrate to
proper class RTC drivers if any and use CONFIG_RTC_SYSTOHC instead.

Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index e49502a..56442d2 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -25,6 +25,7 @@
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select RTC_CLASS
 	select RTC_DRV_M48T59
+	select RTC_SYSTOHC
 	select HAVE_DMA_ATTRS
 	select HAVE_DMA_API_DEBUG
 	select HAVE_ARCH_JUMP_LABEL if SPARC64
@@ -35,7 +36,6 @@
 	select HAVE_BPF_JIT
 	select HAVE_DEBUG_BUGVERBOSE
 	select GENERIC_SMP_IDLE_THREAD
-	select GENERIC_CMOS_UPDATE
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_STRNCPY_FROM_USER
 	select GENERIC_STRNLEN_USER