Convert CONFIG_CLOCKS to Kconfig

This converts the following to Kconfig:
   CONFIG_CLOCKS

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/bitmain_antminer_s9_defconfig b/configs/bitmain_antminer_s9_defconfig
index 1c76578..9775ee1 100644
--- a/configs/bitmain_antminer_s9_defconfig
+++ b/configs/bitmain_antminer_s9_defconfig
@@ -26,6 +26,7 @@
 CONFIG_BOOTDELAY=3
 CONFIG_USE_PREBOOT=y
 # CONFIG_DISPLAY_CPUINFO is not set
+CONFIG_CLOCKS=y
 CONFIG_SPL_STACK_R=y
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="antminer> "