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/socfpga_mcvevk_defconfig b/configs/socfpga_mcvevk_defconfig
index 8be8b85..4d16ec3 100644
--- a/configs/socfpga_mcvevk_defconfig
+++ b/configs/socfpga_mcvevk_defconfig
@@ -73,3 +73,4 @@
 CONFIG_USB_GADGET_DWC2_OTG=y
 CONFIG_USB_GADGET_DOWNLOAD=y
 # CONFIG_SPL_WDT is not set
+CONFIG_SYS_TIMER_COUNTS_DOWN=y