gpio: shared: fix a false-positive sharing detection with reset-gpios

gpio: shared: fix a false-positive sharing detection with reset-gpios

After scanning the devicetree, we remove all entries that have only one
reference, while creating GPIO shared proxies for the remaining, shared
entries. However: for the reset-gpio corner-case, we will have two
references for a "reset-gpios" pin that's not really shared. In this
case one will come from the actual consumer fwnode and the other from
the potential auxiliary reset-gpio device. This causes the GPIO core to
create unnecessary GPIO shared proxy devices for pins that are not
really shared.

Add a function that can detect this situation and remove entries that
have exactly two references but one of them is a reset-gpio.

Fixes: 7b78b26757e0 ("gpio: shared: handle the reset-gpios corner case")
Link: https://lore.kernel.org/r/20260108-gpio-shared-false-positive-v1-1-5dbf8d1b2f7d@oss.qualcomm.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>