[PATCH] pciehp: handle sticky power-fault status

This patch disables power fault, MRL sensor and presence detection
interrupts when a PCIe slot is powered-off and enables those
interrupts when it is powered-on again. This is necessary to prevent
the associated events from causing an endless cycle of interrupts
due to the power-fault bit, which stays set till power is restored
to the slot.

Signed-off-by: Thomas Schaefer <thomas.schaefer@kontron.com>
Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>