gpio: vf610: Switch to gpio-mmio

After adding a pinctrl flag to gpio-mmio we can use it
for driving gpio-vf610.

The existing code has the same semantics and the generic
gpio-mmio, including reading from the data out register
when the direction is set to input, and it can also handle
the absence of the direction register better than the
current driver: we get the direction from the shadow
direction registers in gpio-mmio instead.

Since gpio-mmio has an internal spinlock we can drop the
direction-protecting spinlock from the driver.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Tested-by: Haibo Chen <haibo.chen@nxp.com>
Link: https://lore.kernel.org/r/20250219-vf610-mmio-v3-2-588b64f0b689@linaro.org


Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>