x86: coreboot: Don't setup MTRR when booting from coreboot

This currently hangs and it is not necessary in any case. Drop the code
when booting from coreboot.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/x86/lib/init_helpers.c

@@ -18,6 +18,9 @@ int init_cache_f_r(void)
 		 IS_ENABLED(CONFIG_FSP_VERSION2);
 	int ret;
 
+	if (!ll_boot_init())
+		return 0;
+
 	do_mtrr &= !IS_ENABLED(CONFIG_FSP_VERSION1) &&
 		!IS_ENABLED(CONFIG_SYS_SLIMBOOTLOADER);
 
@@ -31,9 +34,6 @@ int init_cache_f_r(void)
 			return ret;
 	}
 
-	if (!ll_boot_init())
-		return 0;
-
 	/* Initialise the CPU cache(s) */
 	return init_cache();
 }