scripts/genpinctrl: Add config for USB signals generation

Includes USB, OTG_FS and OTG_HS various signals.
This only concerns signals that are configured using alternate.
Signals requiring analog configuration are left a part for now on.
This could lead to situations where only USB_NOE signals are
available on some SoCs (other signals will require a script update
to be generated).


Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>