regulator: ab8500: Add missing volt_table setting for AB8540_LDO_TVOUT

This is required for regulator_list_voltage_table() to properly work.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>