console/post_codes: Add post codes for memory param prep callback

This change adds two new post codes to indicate start and end of
memory param preparation in callbacks to SoC/mainboard code:
1. 0x34: Start of memory preparation
2. 0x36: End of memory preparation

These post codes are already used in coreboot. This change just
ensures that the codes are defined in post_codes.h for easy lookup.

These post codes are useful if SoC/mainboard decides to do a reset of
the platform before returning back to memory initialization.

Change-Id: I065518caedb7943d960a8a5c8708823b8eb3246d
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/29150
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/include/console/post_codes.h

@@ -81,6 +81,22 @@
  */
 #define POST_ENTRY_C_START			0x13
 
+/**
+ * \brief Pre-memory init preparation start
+ *
+ * Post code emitted in romstage before making callbacks to allow SoC/mainboard
+ * to prepare params for FSP memory init.
+ */
+#define POST_MEM_PREINIT_PREP_START		0x34
+
+/**
+ * \brief Pre-memory init preparation end
+ *
+ * Post code emitted in romstage after returning from SoC/mainboard callbacks
+ * to prepare params for FSP memory init.
+ */
+#define POST_MEM_PREINIT_PREP_END		0x36
+
 /**
  * \brief Pre call to RAM stage main()
  *