Convert CONFIG_USB_KEYBOARD to Kconfig

This converts the following to Kconfig:
   CONFIG_USB_KEYBOARD

Signed-off-by: Simon Glass <sjg@chromium.org>
[trini: Fixup MPC86* configs]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/Cyrus_P5020_defconfig b/configs/Cyrus_P5020_defconfig
index 6495440..5eb5660 100644
--- a/configs/Cyrus_P5020_defconfig
+++ b/configs/Cyrus_P5020_defconfig
@@ -26,4 +26,5 @@
 CONFIG_FSL_ESPI=y
 CONFIG_USB=y
 CONFIG_USB_STORAGE=y
+CONFIG_USB_KEYBOARD=y
 CONFIG_OF_LIBFDT=y