timestamps: Rename timestamps to make names more consistent

This patch aims to make timestamps more consistent in naming,
to follow one pattern. Until now there were many naming patterns:
- TS_START_*/TS_END_*
- TS_BEFORE_*/TS_AFTER_*
- TS_*_START/TS_*_END
This change also aims to indicate, that these timestamps can be used
to create time-ranges, e.g. from TS_BOOTBLOCK_START to TS_BOOTBLOCK_END.

Signed-off-by: Jakub Czapiga <jacz@semihalf.com>
Change-Id: I533e32392224d9b67c37e6a67987b09bf1cf51c6
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62019
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
diff --git a/src/security/vboot/vboot_loader.c b/src/security/vboot/vboot_loader.c
index 482c6fb..1c4343b 100644
--- a/src/security/vboot/vboot_loader.c
+++ b/src/security/vboot/vboot_loader.c
@@ -52,10 +52,10 @@
 
 		printk(BIOS_DEBUG, "VBOOT: Loading verstage.\n");
 
-		timestamp_add_now(TS_START_COPYVER);
+		timestamp_add_now(TS_COPYVER_START);
 		if (cbfs_prog_stage_load(&verstage))
 			die("failed to load verstage");
-		timestamp_add_now(TS_END_COPYVER);
+		timestamp_add_now(TS_COPYVER_END);
 
 		/* verify and select a slot */
 		prog_run(&verstage);