When going into suspend, the HW configuration for MSI-X will
likely be lost. As a consequence, after waking up, all IRQ
causes will be mapped to interrupt 0, and as a consequence we
don't notice the interrupt because in most cases this is an
interrupt for a queue, and getting it doesn't read the other
cause registers.

Fixes: 2e5d4a8f ("iwlwifi: pcie: Add new configuration to enable MSIX")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>