Convert CONFIG_CMD_ECCTEST to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_ECCTEST

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/t3corp_defconfig b/configs/t3corp_defconfig
index 21c4c89..2e5416e 100644
--- a/configs/t3corp_defconfig
+++ b/configs/t3corp_defconfig
@@ -2,6 +2,7 @@
 CONFIG_4xx=y
 CONFIG_TARGET_T3CORP=y
 CONFIG_CMD_CHIP_CONFIG=y
+CONFIG_CMD_ECCTEST=y
 CONFIG_FIT=y
 CONFIG_OF_BOARD_SETUP=y
 CONFIG_BOOTDELAY=5