regulator: 88pm8607: Update update_bit for BUCK2 in pm8607_set_voltage_sel

BUCK2 has the update_bit setting, but current code does not set update_bit
in pm8607_set_voltage_sel.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
1 file changed