mfd: cros_ec: cleanup: Remove EC wrapper functions

Remove the three wrapper functions that talk to the EC without passing all
the desired arguments and just use the underlying communication function
that passes everything in a struct intead.

This is internal code refactoring only. Nothing should change.

Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>