This patch adds a USB device driver for the USBHS device that can be
found on Atmel SAM E70 SoC family. Only the FIFO mode is supported
(as opposed to DMA). It supports LS, FS and HS modes, but defaults to
FS mode as Zephyr does not fully support HS mode yet.
Tested examples on an Atmel SMART SAM E70 Xplained Board:
* usb/cdc_acm
* usb/hid-mouse
* usb/mass
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>