The USB phy should initialize with power-off, and will be powered on
by the USB system when a cable connection is detected.

Having this pm_runtime_get_sync() during probe causes the phy to
*always* be powered on.
Removing it returns to sensible power management.

Fixes: 96be39abSigned-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>