regulator: rt6160: Fix setting suspend voltage

The vsel active level is for the normal voltage, the opposite level is
the suspend voltage.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Reviewed-by: ChiYuan Huang <cy_huang@richtek.com>
Link: https://lore.kernel.org/r/20210616011816.3479406-1-axel.lin@ingics.com


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