arm: socfpga: Move Stratix10 and Agilex SPL common code

Move Stratix10 and Agilex SPL common code to spl_soc64.c.
We are in preparation for new n5x device support.
No functional change in this patch.

Signed-off-by: Siew Chin Lim <elly.siew.chin.lim@intel.com>
Reviewed-by: Ley Foon Tan <ley.foon.tan@intel.com>
diff --git a/arch/arm/mach-socfpga/Makefile b/arch/arm/mach-socfpga/Makefile
index 9e63296..e4c2da9 100644
--- a/arch/arm/mach-socfpga/Makefile
+++ b/arch/arm/mach-socfpga/Makefile
@@ -70,10 +70,12 @@
 ifdef CONFIG_TARGET_SOCFPGA_STRATIX10
 obj-y	+= firewall.o
 obj-y	+= spl_s10.o
+obj-y	+= spl_soc64.o
 endif
 ifdef CONFIG_TARGET_SOCFPGA_AGILEX
 obj-y	+= firewall.o
 obj-y	+= spl_agilex.o
+obj-y	+= spl_soc64.o
 endif
 else
 obj-$(CONFIG_SPL_ATF) += secure_reg_helper.o