armv8/ls1043a: Enable secondary cores

After the secondary cores enter U-Boot, use CONFIG_ARMV8_MULTIENTRY to
make secondary cores excute in spin loop.

Signed-off-by: Hou Zhiqiang <B48286@freescale.com>
Signed-off-by: Mingkai Hu <Mingkai.Hu@freescale.com>
Signed-off-by: Gong Qianyu <Qianyu.Gong@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 10d7c14..3992f69 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -630,6 +630,7 @@
 config TARGET_LS1043ARDB
 	bool "Support ls1043ardb"
 	select ARM64
+	select ARMV8_MULTIENTRY
 	select SUPPORT_SPL
 	help
 	  Support for Freescale LS1043ARDB platform.