net: pse-pd: fix out-of-bounds bitmap access in pse_isr() on 32-bit

net: pse-pd: fix out-of-bounds bitmap access in pse_isr() on 32-bit

In pse_isr(), notifs_mask was declared as a single unsigned long on the
stack (32 bits on 32-bit architectures). For PSE controllers with more
than 32 ports, this causes two problems:

- map_event callbacks could wrote bit positions >= 32 via
  *notifs_mask |= BIT(i), which is undefined behaviour on a 32-bit
  unsigned long and corrupts adjacent stack memory.

- for_each_set_bit(i, &notifs_mask, pcdev->nr_lines) treats
  &notifs_mask as a multi-word bitmap and reads beyond the single
  unsigned long when nr_lines > BITS_PER_LONG.

Fix this by moving notifs_mask out of the stack and into struct pse_irq
as a dynamically allocated bitmap. It is sized with
BITS_TO_LONGS(pcdev->nr_lines) words in devm_pse_irq_helper(), so it
is always wide enough regardless of the host word size.

[Jakub]: No upstream driver currently supports >=32 ports.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://patch.msgid.link/20260415130300.806152-1-kory.maincent@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>