Falco: Enable dynamic TFTP server config

BUG=chrome-os-partner:22049
TEST=TFTP IP address should be provided by DHCP server.

Change-Id: Id495097dc1b29e979c2abc29460196beacbb2053
Reviewed-on: https://gerrit.chromium.org/gerrit/66695
Reviewed-by: Gabe Black <gabeblack@chromium.org>
Commit-Queue: Jay Kim <yongjaek@chromium.org>
Tested-by: Jay Kim <yongjaek@chromium.org>
diff --git a/board/falco/defconfig b/board/falco/defconfig
index bd339fc..72b679d 100644
--- a/board/falco/defconfig
+++ b/board/falco/defconfig
@@ -32,3 +32,6 @@
 CONFIG_DRIVER_SOUND_HDA=y
 CONFIG_DRIVER_TPM_LPC=y
 CONFIG_DRIVER_LYNXPOINT_NO_EHCI=y
+
+# Netboot options
+CONFIG_NETBOOT_DYNAMIC_PARAMS=y