treewide: Replace CONFIG(ARCH_xx) tests

Once we support building stages for different architectures,
such CONFIG(ARCH_xx) tests do not evaluate correctly anymore.

Change-Id: I599995b3ed5c4dfd578c87067fe8bfc8c75b9d43
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42183
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/lib/timestamp.c b/src/lib/timestamp.c
index d10b138..24d80ea 100644
--- a/src/lib/timestamp.c
+++ b/src/lib/timestamp.c
@@ -71,7 +71,7 @@
 	 * Only check boot_cpu() in other stages than
 	 * ENV_PAYLOAD_LOADER on x86.
 	 */
-	if ((!ENV_PAYLOAD_LOADER && CONFIG(ARCH_X86)) && !boot_cpu())
+	if ((!ENV_PAYLOAD_LOADER && ENV_X86) && !boot_cpu())
 		return 0;
 
 	return 1;