i40e: Fix for trace found with S4 state

This patch fixes a problem found in systems when entering
S4 state.  This patch fixes the problem by ensuring that
the misc vector's IRQ is disabled as well.  Without this
patch a stack trace can be seen upon entering S4 state.

Signed-off-by: Carolyn Wyborny <carolyn.wyborny@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>