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>

src/lib/hardwaremain.c

@@ -425,7 +425,7 @@ void main(void)
 
 	/* TODO: Understand why this is here and move to arch/platform code. */
 	/* For MMIO UART this needs to be called before any other printk. */
-	if (CONFIG(ARCH_X86))
+	if (ENV_X86)
 		init_timer();
 
 	/* console_init() MUST PRECEDE ALL printk()! Additionally, ensure