dt-bindings: gpio: altera: correct interrupt-cells

stable inclusion
from stable-v5.10.121
commit ec029087dfef70a89c5ff0c6433bd4da211cbbad
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6CQ

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ec029087dfef70a89c5ff0c6433bd4da211cbbad



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commit 3a21c3ac upstream.

update documentation to correctly state the interrupt-cells to be 2.

Cc: stable@vger.kernel.org
Fixes: 4fd9bbc6 ("drivers/gpio: Altera soft IP GPIO driver devicetree binding")
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>