usb: dwc3: of-simple: Fix warning during unbind

usb: dwc3: of-simple: Fix warning during unbind

In dwc3_of_simple_remove() we are using clk_unprepare() before
doing any clk_disable(). Because of this we see kernel warning
during unbind if we enable Common CLK framework(CCF).
This patch fixes this kernel warning by using clk_disable_unprepare
instead of clk_unprepare().

Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Tested-by: Sören Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>