soc/amd/{cezanne,picasso}: Add TS_START_ROMSTAGE

BUG=b:179092979
TEST=boot guybrush and see romstage tag
  14:finished loading romstage                         2,683,151 (10,079)
   1:start of romstage                                 2,683,159 (8)
 970:<unknown>                                         2,683,386 (227)
  15:starting LZMA decompress (ignore for x86)         2,683,391 (5)
  16:finished LZMA decompress (ignore for x86)         2,717,867 (34,476)

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: Ib8b3fe909140e05a89b74df526bf4f81799ad915
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55398
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/amd/cezanne/romstage.c b/src/soc/amd/cezanne/romstage.c
index d3e1bd7..b64fb4b 100644
--- a/src/soc/amd/cezanne/romstage.c
+++ b/src/soc/amd/cezanne/romstage.c
@@ -9,10 +9,14 @@
 #include <console/console.h>
 #include <fsp/api.h>
 #include <program_loading.h>
+#include <timestamp.h>
 
 asmlinkage void car_stage_entry(void)
 {
+	timestamp_add_now(TS_START_ROMSTAGE);
+
 	post_code(0x40);
+
 	console_init();
 
 	post_code(0x41);
diff --git a/src/soc/amd/picasso/romstage.c b/src/soc/amd/picasso/romstage.c
index 7e20768..d3ceec5 100644
--- a/src/soc/amd/picasso/romstage.c
+++ b/src/soc/amd/picasso/romstage.c
@@ -9,11 +9,15 @@
 #include <console/console.h>
 #include <fsp/api.h>
 #include <program_loading.h>
+#include <timestamp.h>
 #include <types.h>
 
 asmlinkage void car_stage_entry(void)
 {
+	timestamp_add_now(TS_START_ROMSTAGE);
+
 	post_code(0x40);
+
 	console_init();
 
 	post_code(0x42);