usb: kbd: select SYS_STDIO_DEREGISTER

If SYS_STDIO_DEREGISTER is not selected and USB_KEYBOARD is selected
U-Boot cannot be built due to missing function stdio_deregister_dev.

So USB_KEYBOARD should select SYS_STDIO_DEREGISTER.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

drivers/usb/Kconfig

@@ -71,6 +71,7 @@ config USB_STORAGE
 
 config USB_KEYBOARD
 	bool "USB Keyboard support"
+	select SYS_STDIO_DEREGISTER
 	---help---
 	  Say Y here if you want to use a USB keyboard for U-Boot command line
 	  input.