regulator: rk808: Remove rk817_set_suspend_voltage function

The implement is exactly the same as rk808_set_suspend_voltage, so just
use rk808_set_suspend_voltage instead.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Link: https://lore.kernel.org/r/20191008010628.8513-3-axel.lin@ingics.com


Signed-off-by: Mark Brown <broonie@kernel.org>