pinctrl: amd: Detect and mask spurious interrupts

Leverage gpiochip_line_is_irq to check whether a pin has an irq
associated with it. The previous check ("irq == 0") didn't make much
sense. The irq variable refers to the pinctrl irq, and has nothing do to
with an individual pin.

On some systems, during suspend/resume cycle, the firmware leaves
an interrupt enabled on a pin that is not used by the kernel.
Without this patch that caused an interrupt storm.

Cc: stable@vger.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217315
Signed-off-by: Kornel Dulęba <korneld@chromium.org>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20230421120625.3366-4-mario.limonciello@amd.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>