phy: usb: fix driver to defer on clk_get defer

Handle defer on clk_get because the new SCMI clock driver comes
up after this driver.

Signed-off-by: Al Cooper <alcooperx@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>