arm64: defconfig: enable RX-8581 config option

Enable support for RX-8571/RX-8581 RTC by turning on
CONFIG_RTC_DRV_RX8581 as module.
Signed-off-by: NBiju Das <biju.das@bp.renesas.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

arch/arm64/configs/defconfig

@@ -605,6 +605,7 @@ CONFIG_EDAC_GHES=y
 CONFIG_RTC_CLASS=y
 CONFIG_RTC_DRV_MAX77686=y
 CONFIG_RTC_DRV_RK808=m
+CONFIG_RTC_DRV_RX8581=m
 CONFIG_RTC_DRV_S5M=y
 CONFIG_RTC_DRV_DS3232=y
 CONFIG_RTC_DRV_EFI=y