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_de10_standard_defconfig b/configs/socfpga_de10_standard_defconfig
index 412b0da..dbf979e 100644
--- a/configs/socfpga_de10_standard_defconfig
+++ b/configs/socfpga_de10_standard_defconfig
@@ -72,3 +72,4 @@
 CONFIG_USB_GADGET_DWC2_OTG=y
 CONFIG_USB_GADGET_DOWNLOAD=y
 # CONFIG_SPL_WDT is not set
+CONFIG_SYS_TIMER_COUNTS_DOWN=y