Add "simplified_beacon" frame support.

[Adminiuga]

Frame received: 0x1f27000e0007000a89d212190000

case ZM_CMD_BEACON:
    {
        const uint BEACON_LEN = 7;

        deCONZ::Beacon b;

        const uint8_t *p = cmd->buffer.data;
        quint16 len = cmd->buffer.len;

        while (len >= BEACON_LEN)
        {
            p = get_u16_le(p, &b.source);
            p = get_u16_le(p, &b.panId);
            p = get_u8_le(p, &b.channel);
            p = get_u8_le(p, &b.flags);
            p = get_u8_le(p, &b.updateId);

            emit beacon(b);

            len -= BEACON_LEN;

        }
    }

https://github.com/dresden-elektronik/deconz-rest-plugin/issues/158#issuecomment-502687797

[damarco]

Thanks, @Adminiuga !