AS923: Using LoRa modulation comatible DR as default
AS923: Using LoRa modulation comatible DR as default

DR7 is used for FSK in AS932 region. As a default max DR, we should use a LoRa modulation
compatible data rate. Ofcourse if a device wishes to use FSK, it can set DR7 using set_data_rate() API
and turning off ADR, or an NS can configure a new channel for the device utilizing DR7.

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