Documentation: PM: Drop pme_interrupt reference

Documentation: PM: Drop pme_interrupt reference

`pme_interrupt` was dropped from `struct pci_dev` as part of commit
8370c2dc4c7b ("PCI / PM: Drop pme_interrupt flag from struct pci_dev"),
but the Documentation still includes this member.

Remove it from the documentation as well and update it to have the missing
`pme_poll` member instead.

Fixes: 8370c2dc4c7b ("PCI / PM: Drop pme_interrupt flag from struct pci_dev")
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>