Migrate USB_EHCI_TEGRA from headers to Kconfig

Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Cc: Tom Warren <twarren@nvidia.com>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Cc: Peter.Chubb@data61.csiro.au
Cc: Lucas Stach <dev@lynxeye.de>
Cc: Stefan Agner <stefan.agner@toradex.com>
Cc: Alban Bedel <alban.bedel@avionic-design.de>
Cc: Allen Martin <amartin@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>