main: Drop more #ifdefs

Now that many things are converted to Kconfig we can drop most of the

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/main.c b/common/main.c
index 9802bed..07b34bf 100644
--- a/common/main.c
+++ b/common/main.c
@@ -24,15 +24,15 @@
 
 	p = env_get("preboot");
 	if (p != NULL) {
-# ifdef CONFIG_AUTOBOOT_KEYED
-		int prev = disable_ctrlc(1);	/* disable Control C checking */
-# endif
+		int prev = 0;
+
+		if (IS_ENABLED(CONFIG_AUTOBOOT_KEYED))
+			prev = disable_ctrlc(1); /* disable Ctrl-C checking */
 
 		run_command_list(p, -1, 0);
 
-# ifdef CONFIG_AUTOBOOT_KEYED
-		disable_ctrlc(prev);	/* restore Control C checking */
-# endif
+		if (IS_ENABLED(CONFIG_AUTOBOOT_KEYED))
+			disable_ctrlc(prev);	/* restore Ctrl-C checking */
 	}
 #endif /* CONFIG_PREBOOT */
 }
@@ -44,17 +44,15 @@
 
 	bootstage_mark_name(BOOTSTAGE_ID_MAIN_LOOP, "main_loop");
 
-#ifdef CONFIG_VERSION_VARIABLE
-	env_set("ver", version_string);  /* set version variable */
-#endif /* CONFIG_VERSION_VARIABLE */
+	if (IS_ENABLED(CONFIG_VERSION_VARIABLE))
+		env_set("ver", version_string);  /* set version variable */
 
 	cli_init();
 
 	run_preboot_environment_command();
 
-#if defined(CONFIG_UPDATE_TFTP)
-	update_tftp(0UL, NULL, NULL);
-#endif /* CONFIG_UPDATE_TFTP */
+	if (IS_ENABLED(CONFIG_UPDATE_TFTP))
+		update_tftp(0UL, NULL, NULL);
 
 	s = bootdelay_process();
 	if (cli_process_fdt(&s))