Convert CONFIG_SYS_FAULT_ECHO_LINK_DOWN to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_FAULT_ECHO_LINK_DOWN

Cc: Ramon Fried <rfried.dev@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/syzygy_hub_defconfig b/configs/syzygy_hub_defconfig
index cbc6208..43684de 100644
--- a/configs/syzygy_hub_defconfig
+++ b/configs/syzygy_hub_defconfig
@@ -43,6 +43,7 @@
 CONFIG_CMD_EXT4_WRITE=y
 CONFIG_ENV_OVERWRITE=y
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
+CONFIG_SYS_FAULT_ECHO_LINK_DOWN=y
 CONFIG_SPL_DM_SEQ_ALIAS=y
 CONFIG_FPGA_XILINX=y
 CONFIG_FPGA_ZYNQPL=y