usb: chipidea: tegra: Rename UDC to USB

usb: chipidea: tegra: Rename UDC to USB

Rename all occurrences in the code from "udc" to "usb" and change the
Kconfig entry in order to show that this driver supports USB modes other
than device-only mode. The follow up patch will add host-mode support and
it will be cleaner to perform the renaming separately, i.e. in this patch.

Tested-by: Matt Merhar <mattmerhar@protonmail.com>
Tested-by: Nicolas Chauvet <kwizart@gmail.com>
Tested-by: Peter Geis <pgwipeout@gmail.com>
Tested-by: Ion Agorria <ion@agorria.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Acked-by: Peter Chen <peter.chen@kernel.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20201218120246.7759-5-digetx@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>