ice: Use sleepable locks in shared code

[kbowling]

Summary

The Intel shared code can wait for firmware resources while holding its
OS abstraction locks.  FreeBSD mapped these locks to mutexes, which
cannot be held across a voluntary sleep.  Concurrent PF rebuilds
therefore trigger WITNESS when RSS profile updates contend for the
firmware change lock.

Map the shared-code lock abstraction to exclusive sx locks.  This also
covers tunnel and flow-profile operations which can reach the same
firmware wait while serialized.

Validated with WITNESS on a dual-port Intel E835.  Sixteen CORE resets
rebuilt both PFs without lock warnings, reset failures, or watchdogs.
Ten interface down/up cycles and twenty promiscuous-filter cycles also
completed cleanly.

MFC after:      2 weeks
Sponsored by:   BBOX.io

[erj]

The more I work on Linux the more I think these were the appropriate type of lock to be using for the shared code.