x86: config: Enable dhrystone command for link

Enable this command so we can get an approximate performance measurement.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/configs/chromebook_link64_defconfig b/configs/chromebook_link64_defconfig
index 3ab34cd..749cfd4 100644
--- a/configs/chromebook_link64_defconfig
+++ b/configs/chromebook_link64_defconfig
@@ -86,4 +86,5 @@
 CONFIG_VIDEO_IVYBRIDGE_IGD=y
 CONFIG_CONSOLE_SCROLL_LINES=5
 CONFIG_USE_PRIVATE_LIBGCC=y
+CONFIG_CMD_DHRYSTONE=y
 CONFIG_TPM=y