vboot: indicate verstage loading on console

There was no indication of verstage being loaded. Provide this
output so that one can follow the flow from console messages.

Change-Id: I67ae6bb334608fe10a4a12fe690498afaf6b8366
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/10195
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/vendorcode/google/chromeos/vboot2/vboot_loader.c

@@ -94,6 +94,8 @@ static int vboot_loader_active(struct prog *prog)
 			.name = CONFIG_CBFS_PREFIX "/verstage",
 		};
 
+		printk(BIOS_DEBUG, "VBOOT: Loading verstage.\n");
+
 		/* load verstage from RO */
 		if (cbfs_load_prog_stage(CBFS_DEFAULT_MEDIA, &verstage))
 			die("failed to load verstage");