Convert CONFIG_SYS_TIMER_COUNTS_DOWN to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_TIMER_COUNTS_DOWN

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/bitmain_antminer_s9_defconfig b/configs/bitmain_antminer_s9_defconfig
index cbcbc9b..0225717 100644
--- a/configs/bitmain_antminer_s9_defconfig
+++ b/configs/bitmain_antminer_s9_defconfig
@@ -93,4 +93,5 @@
 # CONFIG_WATCHDOG is not set
 CONFIG_WDT=y
 CONFIG_WDT_CDNS=y
+CONFIG_SYS_TIMER_COUNTS_DOWN=y
 # CONFIG_EFI_LOADER is not set