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/stratix10/platform.mk b/plat/intel/soc/stratix10/platform.mk
index 34674b0..b7c70ff 100644
--- a/plat/intel/soc/stratix10/platform.mk
+++ b/plat/intel/soc/stratix10/platform.mk
@@ -37,7 +37,7 @@
 		plat/intel/soc/stratix10/plat_storage.c			\
                 plat/intel/soc/common/bl2_plat_mem_params_desc.c	\
 		plat/intel/soc/stratix10/soc/s10_reset_manager.c	\
-		plat/intel/soc/stratix10/soc/s10_handoff.c		\
+		plat/intel/soc/common/soc/socfpga_handoff.c		\
 		plat/intel/soc/stratix10/soc/s10_clock_manager.c	\
 		plat/intel/soc/stratix10/soc/s10_pinmux.c		\
 		plat/intel/soc/stratix10/soc/s10_memory_controller.c	\
@@ -63,7 +63,6 @@
 			plat/intel/soc/stratix10/soc/s10_reset_manager.c\
 			plat/intel/soc/stratix10/soc/s10_pinmux.c	\
 			plat/intel/soc/stratix10/soc/s10_clock_manager.c\
-			plat/intel/soc/stratix10/soc/s10_handoff.c	\
 			plat/intel/soc/stratix10/soc/s10_mailbox.c
 
 PROGRAMMABLE_RESET_ADDRESS	:= 0