Add US version of Xiaomi Humidifier

The xiaomi_miio component only supports the Chinese version of the humidifier (zhimi.humidifier.ca1) The US version (zhimi.humidifier.ca1) is not recognized.
Python-miio already supports it and it does not look like it requires too drastic changes https://github.com/rytilahti/python-miio/pull/493

Thanks!