usb: host: xhci-plat: Improve clock handling in probe()

usb: host: xhci-plat: Improve clock handling in probe()

It is always better to acquire all the clock resources first and
then do the clock operations.

This patch acquires all the optional clocks first and then calls
corresponding prepare_enable().

There is no functional change.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230121145853.4792-8-biju.das.jz@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>