i40e: shutdown all IRQs and disable MSI-X when suspended

i40e: shutdown all IRQs and disable MSI-X when suspended

On some platforms with a large number of CPUs, we will allocate many IRQ
vectors. When hibernating, the system will attempt to migrate all of the
vectors back to CPU0 when shutting down all the other CPUs. It is
possible that we have so many vectors that it cannot re-assign them to
CPU0. This is even more likely if we have many devices installed in one
platform.

The end result is failure to hibernate, as it is not possible to
shutdown the CPUs. We can avoid this by disabling MSI-X and clearing our
interrupt scheme when the device is suspended. A more ideal solution
would be some method for the stack to properly handle this for all
drivers, rather than on a case-by-case basis for each driver to fix
itself.

However, until this more ideal solution exists, we can do our part and
shutdown our IRQs during suspend, which should allow systems with
a large number of CPUs to safely suspend or hibernate.

It may be worth investigating if we should shut down even further when
we suspend as it may make the path cleaner, but this was the minimum fix
for the hibernation issue mentioned here.

Testing-hints:
  This affects systems with a large number of CPUs, and with multiple
  devices enabled. Without this change, those platforms are unable to
  hibernate at all.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>