i40evf: Add additional check for reset

If the driver happens to read a register during the time in which the
device is undergoing reset, it will receive a value of 0xdeadbeef
instead of a valid value. Unfortunately, the driver may misinterpret
this as a valid value, especially if it's just looking for individual
bits.

Add an explicit check for this value when we are looking for admin queue
errors, and trigger reset recovery if we find it.

Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>