mainboard: Remove unused include <timestamp.h>

Change-Id: Id05fc39c0c0d0560e34e55f793060d29df82d026
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32676
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Reviewed-by: Sumeet R Pawnikar <sumeet.r.pawnikar@intel.com>

src/mainboard/google/cheza/mainboard.c

@@ -16,7 +16,6 @@
 #include <device/device.h>
 #include <bootblock_common.h>
 #include <gpio.h>
-#include <timestamp.h>
 #include <soc/usb.h>
 
 static struct usb_board_data usb1_board_data = {

src/mainboard/google/mistral/bootblock.c

@@ -14,7 +14,6 @@
  */
 
 #include <bootblock_common.h>
-#include <timestamp.h>
 
 void bootblock_mainboard_init(void)
 {

src/mainboard/google/mistral/mainboard.c

@@ -15,7 +15,6 @@
 
 #include <device/device.h>
 #include <bootblock_common.h>
-#include <timestamp.h>
 #include <vendorcode/google/chromeos/chromeos.h>
 #include <soc/usb.h>