arch/x86: Increase TIMESTAMP region size to 0x200

With the recent change 4c518e1 (timestamp: Add timestamps for TPM
communication) to add more timestamps for TPM communication, now we
are overflowing the TIMESTAMP region in verstage. This change
increases TIMESTAMP region size to 512 bytes to accomodate this.

BUG=b:79888151, b:79974682

Change-Id: I94c5403f256f0176d10ac61e9e1f60adf80db08b
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/26360
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>

src/arch/x86/car.ld

@@ -60,7 +60,7 @@
 	 * backing store once cbmem comes online. Therefore, this data needs
 	 * to reside in the migrated area (between _car_relocatable_data_start
 	 * and _car_relocatable_data_end). */
-	TIMESTAMP(., 0x100)
+	TIMESTAMP(., 0x200)
 #if IS_ENABLED(CONFIG_COMMONLIB_STORAGE)
 	_car_drivers_storage_start = .;
 	. += 256;