usb: dwc3: Determine connection speed for HS PHY

DP/DM linestate is needed by the QUSB2 PHY driver to configure the
polarity of DP/DM transition triggers for exiting low power mode.
This was previously available via the  QUSB2PHY_PORT_UTMI_STATUS
PHY register which is now deprecated. In order to correctly determine
the interrupt polarity we need to pass the current operating speed
to the QUSB2 PHY driver. The PHY driver uses mode, speed and
cable connection status to determine the linestate and configure
interrupt polarities for wake up. Add logic to determine operating
speed for host and device mode cases.

CRs-Fixed: 1083141
Change-Id: Iaede1269f514a314bd9717a33100f748e7753b2a
Signed-off-by: Devdutt Patnaik <dpatnaik@codeaurora.org>
Signed-off-by: Mayank Rana <mrana@codeaurora.org>