meraki-3a7ae83

ipq806x: mr52: mux bit-banged mdio pins to gpio function

The "virtual,mdio-gpio" bus on the Meraki MR52 muxed GPIO_0/GPIO_1 to
the SoC's dedicated "mdio" function via the shared mdio0_pins_active
group while also requesting them as GPIOs for the bit-banged MDIO
driver. Since commit cc85cb96e2e4 ("pinctrl: qcom: make the pinmuxing
strict") the pinctrl core rejects a GPIO claim on pins already claimed
by a non-GPIO mux function:

  ipq8064-pinctrl 800000.pinmux: pin GPIO_1 already requested by soc:mdio;
  cannot claim for 800000.pinmux:513

so mdio_gpio_probe() fails, the MDIO bus is never registered and no
PHYs get attached to the ethernet interfaces.

Mux the pins to the "gpio" function in a board-local mdio_gpio0_pins
group instead, matching the onhub pattern; the GPIO request is allowed
because the gpio function is marked as a GPIO pin function.

Assisted-by: opencode:big-pickle
Signed-off-by: Rafal Boni <rafal.boni@gmail.com>