iavf: simplify mutex_trylock+sleep loops

iavf: simplify mutex_trylock+sleep loops

This pattern appears in two places in the iavf source code:
  while (!mutex_trylock(...))
      usleep_range(...);

That's just mutex_lock with extra steps.
The pattern is a leftover from when iavf used bit flags instead of
mutexes for locking. Commit 5ac49f3c2702 ("iavf: use mutexes for locking
of critical sections") replaced test_and_set_bit with !mutex_trylock,
preserving the pattern.

Simplify it to mutex_lock.

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://lore.kernel.org/r/20231027175941.1340255-3-jacob.e.keller@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>