usb: phy: Don't free phy memory from remove() API

USB PHY drivers are using managed allocation (i.e. devm_kzalloc())
with its probe() API. Hence remove usage of kfree() from remove()
API as allocated memory would be freed on driver detach itself.
This avoids multiple free of allocated PHY related memory.

Change-Id: Ia89bebe3d9d4d6020a5c72247e0f2970a1e2dd94
Signed-off-by: Mayank Rana <mrana@codeaurora.org>