regulator: tps65910: use appropriate variable names.

Renaming the variables "table" to "voltage_table" and
"table_len" to "n_voltages" of regulator information
to have more meaningful.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>