usb: fotg210: Move clock handling to core

usb: fotg210: Move clock handling to core

Grab the optional silicon block clock, prepare and enable it in
the core before proceeding to prepare the host or peripheral
driver. This saves duplicate code and also uses the simple
devm_clk_get_optional_enabled() to do everything we really
want to do.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230103-gemini-fotg210-usb-v2-4-100388af9810@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>