usb: gadget: omap_udc: Make it CCF clk API compatible

usb: gadget: omap_udc: Make it CCF clk API compatible

The driver, OMAP1 specific, now omits clk_prepare/unprepare() steps, not
supported by OMAP1 custom implementation of clock API.  However, non-CCF
stubs of those functions exist for use on such platforms until converted
to CCF.

Update the driver to be compatible with CCF implementation of clock API.

Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Link: https://lore.kernel.org/r/20220402112658.130191-1-jmkrzyszt@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>