usb: dwc3: ep0: add LPM handling

On device loading the driver enables LPM and the acceptance of U1 and U2
states. The [Set|Clear]Feature requests for "U1/U2" are forwarded
directly to the hardware and allow / forbid the initiation of the low
power links.

Change-Id: I743f0ce83169ed9c3aef904912aec73d08a263b5
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
[pkondeti@codeaurora.org: resolved merge conflicts]
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
3 files changed