bluez5: fix rounding error on hardware volume conversion
Ensure the conversions between spa_bt_volume_linear_to_hw and spa_bt_volume_hw_to_linear are reversible when operating on hardware volume.
Related to #1468 (closed)
Ensure the conversions between spa_bt_volume_linear_to_hw and spa_bt_volume_hw_to_linear are reversible when operating on hardware volume.
Related to #1468 (closed)