clk: Rename clk_get_optional_nodev

This normalizes the name of this accessor function to put "_optional" last.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Link: https://lore.kernel.org/r/20211222171114.3091780-2-seanga2@gmail.com