usb: remove ehci-w90x900 driver

The ARM w90x900 platform is getting removed, so this driver is obsolete.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20190809202749.742267-16-arnd@arndb.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>