Can you just send a patch to the Armada DTS file adding these ranges?

I looked at some other November/December-ish commits into the DT, and in 
the end, this is the patch that I needed to add to my board-specific DTS:

 / {
        gpio_i2c {
                compatible = "i2c-gpio";
                sda-gpios = <&gpio0 25 (GPIO_ACTIVE_HIGH | 
GPIO_OPEN_DRAIN)>;
                scl-gpios = <&gpio0 24 (GPIO_ACTIVE_HIGH | 
GPIO_OPEN_DRAIN)>;
                i2c-gpio.delay-us = <1>;
                #address-cells = <1>;
                #size-cells = <0>;
+               pinctrl-names = "default";
+               pinctrl-0 = <&uart1_pins_i2c_bb>;
        };
 };
 
-&uart1_pins {
+&pinctrl {
+       uart1_pins_i2c_bb: uart1-pins-i2c-bb {
+               marvell,pins = "mpp24", "mpp25";
+               marvell,function = "gpio";
+       };
+};
+
+&mikro_uart_pins {
        status = "disabled";
 };

The missing bit was making sure that the "i2c-gpio" instantiation sees a 
correct pinctrl-names and pinctrl-0 properties.

I think there's probably nothing to fix upstream here; I think it could be 
considered common knowledge than one has to patch the pinctrl block in DT 
in order to re-purpose a set of pins from, say, UART to GPIO. What confused 
me is that pre-5.7, this used to work without setting the pinctrl to "gpio" 
explicitly.

With kind regards,
Jan