USB: host: ohci-at91: depend on OF

Make the driver depend on CONFIG_OF and remove the now useless #ifdef

Also, fix the Kconfig indentation.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>