usb: dwc3: Add support of disable L1 in HS mode

On some platforms, L1 in HS mode is not supported.
Add support to disable L1 in HS mode on those
platforms by default through dt.

Change-Id: I624bde1e091e6e864bf7f7af93804c3728374d0d
Signed-off-by: Udipto Goswami <ugoswami@codeaurora.org>