clk: Fix clk func names in comments

clk function names in comments should be prefix with
clk instead of clock.

Fix it.

Cc: Simon Glass <sjg@chromium.org>
Cc: Tom Rini <trini@konsulko.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Simon Glass <sjg@chromium.org>