ARM: dts: msm: ARM: dts: msm: Enable Secondary Controller for QCM6490 IOT

Enable USB2 for iot targets.
Also, Add lpm Disable flag for secondary controller to
avoid entering lpm during active transfers.

This helps to avoid failures during mtp transfers.

Change-Id: If289917470e7780efa5962c2d0f7a07c7f6f0aa5