intel: Refactor common platform code [1/5]

Pull out handoff driver to intel/soc/ common directory as they can be
shared by both Agilex and Stratix10 platform.

Share platform_def header between both Agilex and Stratix10 and store
platform specific definitions in socfpga_plat_def.h

Signed-off-by: Hadi Asyrafi <muhammad.hadi.asyrafi.abdul.halim@intel.com>
Change-Id: I8eff1afd7ee71704a36a54fad732ede4f557878d
diff --git a/plat/intel/soc/agilex/bl2_plat_setup.c b/plat/intel/soc/agilex/bl2_plat_setup.c
index e9ab928..fa9a6a5 100644
--- a/plat/intel/soc/agilex/bl2_plat_setup.c
+++ b/plat/intel/soc/agilex/bl2_plat_setup.c
@@ -18,7 +18,6 @@
 #include <socfpga_private.h>
 
 #include "agilex_clock_manager.h"
-#include "agilex_handoff.h"
 #include "agilex_mailbox.h"
 #include "agilex_memory_controller.h"
 #include "agilex_pinmux.h"
@@ -28,6 +27,7 @@
 
 #include "ccu/ncore_ccu.h"
 #include "qspi/cadence_qspi.h"
+#include "socfpga_handoff.h"
 #include "wdt/watchdog.h"
 
 
@@ -59,7 +59,7 @@
 
 	generic_delay_timer_init();
 
-	if (agilex_get_handoff(&reverse_handoff_ptr))
+	if (socfpga_get_handoff(&reverse_handoff_ptr))
 		return;
 	config_pinmux(&reverse_handoff_ptr);
 	boot_source = reverse_handoff_ptr.boot_source;