regulator: lochnagar: Fix n_voltages setting for VDDCORE

With current n_voltages setting, regulator_list_voltage will return
-EINVAL when selector >=57. The highest selector is 0x41, so the
n_voltages should be 0x41+1, i.e. 66.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>