regulator: rk808: Add function for ramp delay for buck1/buck2

On rk808 buck1 and buck2 have programmable ramp delays.  Let's add a
function to allow a client of rk808 to set them.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
1 file changed