Fix NULL-deref on runtime suspend

Summary

In the Linux kernel, the following vulnerability has been resolved: phy: qcom: qmp-usb-legacy: fix NULL-deref on runtime suspend Commit 413db06c05e7 ("phy: qcom-qmp-usb: clean up probe initialisation") removed most users of the platform device driver data from the qcom-qmp-usb driver, but mistakenly also removed the initialisation despite the data still being used in the runtime PM callbacks. This bug was later reproduced when the driver was copied to create the qmp-usb-legacy driver. Restore the driver data initialisation at probe to avoid a NULL-pointer dereference on runtime suspend. Apparently no one uses runtime PM, which currently needs to be enabled manually through sysfs, with these drivers.