gpio: pca953x: Add support for level-triggered interrupts

gpio: pca953x: Add support for level-triggered interrupts

[ Upstream commit 417b0f8d08f878615de9481c6e8827fbc8b57ed2 ]

Adds support for level-triggered interrupts in the PCA953x GPIO
expander driver. Previously, the driver only supported edge-triggered
interrupts, which could lead to missed events in scenarios where an
interrupt condition persists until it is explicitly cleared.

By enabling level-triggered interrupts, the driver can now detect and
respond to sustained interrupt conditions more reliably.

Signed-off-by: Potin Lai <potin.lai.pt@gmail.com>
Link: https://lore.kernel.org/r/20250409-gpio-pca953x-level-triggered-irq-v3-1-7f184d814934@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Stable-dep-of: 014a17deb412 ("gpio: pca953x: handle short interrupt pulses on PCAL devices")
Signed-off-by: Sasha Levin <sashal@kernel.org>