x86: Remove coreboot start16 code

Now that coreboot doesn't need the start16 code, remove it. We need
to remove the CONFIG_SYS_X86_RESET_VECTOR option from coreboot.h also.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/configs/coreboot.h b/include/configs/coreboot.h
index 8d3c21f..12d1016 100644
--- a/include/configs/coreboot.h
+++ b/include/configs/coreboot.h
@@ -37,7 +37,7 @@
 #define CONFIG_SYS_COREBOOT
 #undef CONFIG_SHOW_BOOT_PROGRESS
 #define CONFIG_LAST_STAGE_INIT
-
+#define CONFIG_X86_NO_RESET_VECTOR
 
 /*-----------------------------------------------------------------------
  * Watchdog Configuration