drivers/intel/fsp*: Use newly added post codes for memory param prep

This change replaces use of post codes 0x34 and 0x36 in fsp drivers to
instead use POST_MEM_PREINIT_PREP_{START,END} to make it easy to
search from where these post codes are generated during boot flow.

Additionally, it adds POST_MEM_PREINIT_PREP_END to fsp2_0 memory_init
to make it consistent with fsp1_1 memory init.

Change-Id: I307ada1679f212c424e9f7ad2c9d254e24f41fd3
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/29151
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
diff --git a/src/drivers/intel/fsp1_1/raminit.c b/src/drivers/intel/fsp1_1/raminit.c
index 407a0b6..bca9f71 100644
--- a/src/drivers/intel/fsp1_1/raminit.c
+++ b/src/drivers/intel/fsp1_1/raminit.c
@@ -64,7 +64,7 @@
 	 * set to NULL.  This indicates that the FSP code will use the UPD
 	 * region in the FSP binary.
 	 */
-	post_code(0x34);
+	post_code(POST_MEM_PREINIT_PREP_START);
 	fsp_header = params->chipset_context;
 	vpd_ptr = (VPD_DATA_REGION *)(fsp_header->CfgRegionOffset +
 					fsp_header->ImageBase);
@@ -103,7 +103,7 @@
 	if (IS_ENABLED(CONFIG_MMA))
 		setup_mma(&memory_init_params);
 
-	post_code(0x36);
+	post_code(POST_MEM_PREINIT_PREP_END);
 
 	/* Display the UPD data */
 	if (IS_ENABLED(CONFIG_DISPLAY_UPD_DATA))