Convert CONFIG_SYS_WHITE_ON_BLACK to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_WHITE_ON_BLACK

Signed-off-by: Simon Glass <sjg@chromium.org>
[trini: Make this default y on various SoCs]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/brppt1_nand_defconfig b/configs/brppt1_nand_defconfig
index a974e68..9abe617 100644
--- a/configs/brppt1_nand_defconfig
+++ b/configs/brppt1_nand_defconfig
@@ -55,5 +55,6 @@
 CONFIG_USB=y
 CONFIG_USB_MUSB_HOST=y
 CONFIG_USB_STORAGE=y
+CONFIG_SYS_WHITE_ON_BLACK=y
 CONFIG_LCD=y
 CONFIG_OF_LIBFDT=y