When streaming bluetooth audio, the sound is choppy due to the
fact that the default baud rate of the HCI interface is too slow
to handle 16-bit stereo at 48KHz.
The Bluetooth chip is capable of up to 4M baud on the serial port,
so this patch sets the max-speed to 
4000000 in order to properly
stream audio over the Bluetooth.
Fixes: 593816fa2f35 ("arm64: dts: imx: Add Beacon i.MX8m-Mini development kit")
Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
                host-wakeup-gpios = <&gpio2 8 GPIO_ACTIVE_HIGH>;
                device-wakeup-gpios = <&gpio2 7 GPIO_ACTIVE_HIGH>;
                clocks = <&osc_32k>;
+               max-speed = <4000000>;
                clock-names = "extclk";
        };
 };