usb: phy: Enable VDD on probe for Synopsys SS PHY

The Synopsys femto PHY needs VDD to be kept enabled
during the suspend/resume cycles. So enable the
VDD regulator on probe and vote for retention on
suspend and vote for required voltages on resume.
While at it remove the kfree during ssphy_remove
which is not needed as the phy is allocated using
devm_kzalloc which frees up when device is removed.

Change-Id: I72d285403f96ff27008beb84013f65f079d3bbc5
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>