Add bladeRF 2.0 micro xA4 support

[tjmullicani]

No description provided.

[tjmullicani]

Sample run:

tim@sdr1:~/dump1090_rs$ RUSTFLAGS="-C target-cpu=native" cargo r --release -- --driver bladerf
...
[-] using soapysdr driver: driver=bladerf
[INFO] bladerf_open_with_devinfo()
[INFO] bladerf_get_serial() = a6652d1872e449139e4fbcb7cbf4950c
[INFO] setSampleRate(Rx, 0, 4.000000 MHz), actual = 4.000000 MHz
[INFO] setSampleRate(Tx, 0, 4.000000 MHz), actual = 4.000000 MHz
[-] using config: Sdr {
    channel: 0,
    driver: "bladerf",
    setting: None,
    gain: [
        Gain {
            key: "full",
            value: 35.0,
        },
    ],
    antenna: None,
}
[-] Writing gain: full = 35
[-] frequency: Ok(1089999998.0)
[INFO] setSampleRate(Rx, 0, 2.400000 MHz), actual = 2.400000 MHz
[-] sample rate: Ok(2400000.0)

[wcampbell0x2a]

Thanks!