Enable high speed support for USB device framework and usbtty

This patch adds the support for high speed in usb device framework and usbtty
driver. This feature has been kept within a macro CONFIG_USBD_HS, so the board
configuration files have to define this macro to enable high speed support.

Along with that specific peripheral drivers also need to define a function to
let the framework know that the enumeration has happened at high speed.
This function prototype is "int is_usbd_high_speed(void)"

Signed-off-by: Vipin Kumar <vipin.kumar@st.com>
Signed-off-by: Amit Virdi <amit.virdi@st.com>