These APIs aren't used, so remove them. This can be reverted if
we get a user at some point.
Reviewed-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Suggested-by: NMichael Turquette <mturquette@baylibre.com>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>