char/genrtc: x86: remove remnants of asm/rtc.h

Commit 3195ef59cb42 ("x86: Do full rtc synchronization with ntp") had
the side-effect of unconditionally enabling the RTC_LIB symbol on x86,
which in turn disables the selection of the CONFIG_RTC and
CONFIG_GEN_RTC drivers that contain a two older implementations of
the CONFIG_RTC_DRV_CMOS driver.

This removes x86 from the list for genrtc, and changes all references
to the asm/rtc.h header to instead point to the interfaces
from linux/mc146818rtc.h.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
diff --git a/drivers/acpi/acpi_cmos_rtc.c b/drivers/acpi/acpi_cmos_rtc.c
index 81dc750..0980a13 100644
--- a/drivers/acpi/acpi_cmos_rtc.c
+++ b/drivers/acpi/acpi_cmos_rtc.c
@@ -14,7 +14,7 @@
 #include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <asm-generic/rtc.h>
+#include <linux/mc146818rtc.h>
 
 #include "internal.h"