ice: Add a failure injection facility

Add compile-time optional, non-sleeping fail points around every VF
creation resource boundary, before VF VSI reconstruction, and in the
GET_STATS validation pa

ice: Add a failure injection facility

Add compile-time optional, non-sleeping fail points around every VF
creation resource boundary, before VF VSI reconstruction, and in the
GET_STATS validation path.

Provide an ICE-wide wrapper and device selector so other driver
subsystems can add scoped points without duplicating the failpoint
plumbing. Keep the current SR-IOV points and VF selector in an iov
child namespace.

Compile the facility only with options DRIVER_FAILPOINTS. This shared
option avoids a separate kernel option for every driver that provides
test-only injection hooks. Ordinary kernels contain no ICE failpoint
objects or sysctl nodes. Require an exact PF device name and
optionally a VF index before any point can fire. This prevents a stale
test setting from affecting another PF.

The hooks exposed two reset-lifetime defects while validating the
existing SR-IOV review series. A PF reset could discard a firmware VSI
before teardown, and a rebuilt sibling could leave stale switch-filter
state after IOV destroy.

Tested on an E810-XXV with INVARIANTS and WITNESS. All twelve creation
checkpoints rolled back and permitted immediate resource reuse. Forced
reconstruction and malformed GET_STATS failures also preserved sibling
operation and reply cardinality.

Reviewed by: gallatin, nprice, ziaee
MFC after: 2 weeks
Sponsored by: BBOX.io
Differential Revision: https://reviews.freebsd.org/D58940

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