gpio: legacy level interrupt disable API not backwards compatible

[pabigot]

The following was discovered in testing and development of #22659:

In the old GPIO API interrupt configuration was integrated with pin configuration, so an interrupt could be enabled with:

gpio_pin_configure(dev, PIN_IN, GPIO_DIR_IN | GPIO_INT | GPIO_INT_LEVEL);

and disabled within the callback with the idiom:

gpio_pin_configure(dev, PIN_IN, GPIO_DIR_IN);

which, because it did not include any interrupt-related flags, was interpreted to mean disable interrupts.

In the new API interrupt configuration is done with the gpio_pin_interrupt_configure() function. The disable flag is a non-zero value distinct from the non-zero enable flag. For legacy compatibility gpio_pin_configure() extracts interrupt-related flags from its flags parameter and invokes gpio_pin_interrupt_configure() with them, which means the legacy enable command works.

However, the legacy disable command has no interrupt-related flags, which means the new implementation of gio_pin_configure() leaves interrupts enabled.

In the case of level-triggered interrupts where the legacy disable operation is invoked in the callback the application will hang unless GPIO_INT_DISABLE is added to the flags.

[mnkp]

The difference in behavior will be mentioned in the release notes.