irqchip/imgpdc: Fix resource leak, add missing chained handler cleanup on remove

irqchip/imgpdc: Fix resource leak, add missing chained handler cleanup on remove

The driver allocates domain generic chips using
irq_alloc_domain_generic_chips() during probe and sets up chained
handlers using irq_set_chained_handler_and_data(). However, on driver
removal, the generic chips are not freed and the chained handlers are
not removed.

The generic chips remain on the global gc_list and may later be accessed by
generic interrupt chip suspend, resume, or shutdown callbacks after the
driver has been removed, potentially resulting in a use-after-free and
kernel crash.

The chained handlers that were installed in probe for peripheral and
syswake interrupts are also left dangling, which can lead to spurious
interrupts accessing freed memory.

Fix these issues by:

  - Setting IRQ_DOMAIN_FLAG_DESTROY_GC flag in domain->flags, so the
    core code automatically removes generic chips when irq_domain_remove()
    is called

  - Clearing all chained handlers with NULL in pdc_intc_remove()

Fixes: b6ef9161e43a ("irq-imgpdc: add ImgTec PDC irqchip driver")
Signed-off-by: Qingshuang Fu <fuqingshuang@kylinos.cn>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260618021352.661773-1-fffsqian@163.com