ODROID-C5: add command 'source'

Signed-off-by: Dongjin Kim <tobetter@gmail.com>
diff --git a/configs/amlogic/s7d_odroidc5_defconfig b/configs/amlogic/s7d_odroidc5_defconfig
index 22e382d..42a146d 100644
--- a/configs/amlogic/s7d_odroidc5_defconfig
+++ b/configs/amlogic/s7d_odroidc5_defconfig
@@ -111,3 +111,5 @@
 CONFIG_ZSTD=y
 CONFIG_OF_LIBFDT_OVERLAY=y
 CONFIG_LMB_MAX_REGIONS=9
+
+CONFIG_CMD_SOURCE=y