configs: ns3: enable clock subsystem

Enable clock subsystem for ns3.

Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/bcm_ns3_defconfig b/configs/bcm_ns3_defconfig
index a81541e..7e51a92 100644
--- a/configs/bcm_ns3_defconfig
+++ b/configs/bcm_ns3_defconfig
@@ -16,5 +16,7 @@
 CONFIG_OF_CONTROL=y
 CONFIG_DEFAULT_DEVICE_TREE="ns3-board"
 CONFIG_DM=y
+CONFIG_CLK=y
+CONFIG_CLK_CCF=y
 CONFIG_DM_SERIAL=y
 CONFIG_SYS_NS16550=y