arm64: defconfig: add i.MX system controller RTC support

This patch enables CONFIG_RTC_DRV_IMX_SC as module by default.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/configs/defconfig

@@ -586,6 +586,7 @@ CONFIG_RTC_DRV_PL031=y
 CONFIG_RTC_DRV_SUN6I=y
 CONFIG_RTC_DRV_ARMADA38X=y
 CONFIG_RTC_DRV_TEGRA=y
+CONFIG_RTC_DRV_IMX_SC=m
 CONFIG_RTC_DRV_XGENE=y
 CONFIG_DMADEVICES=y
 CONFIG_DMA_BCM2835=m