kernel - Adjust device D_MPSAFE_* flags
* Replace all device D_MPSAFE_* flags with just D_MPSAFE
- Mark CAM's "da" and "cd" devices D_MPSAFE
- Mark dm (device mapper) D_MPSAFE
- Mark memio MPSAFE
- Mark the disk subsystem D_MPSAFE
- Mark the crypto device D_MPSAFE
* Devices marked D_MPSAFE now call their strategy functions without the
mp lock.
* Do a pass on devfs and mark it MNTK_ALL_MPSAFE. devfs was essentially
already MPSAFE but the D_MPSAFE checks have been moved out of devfs
and into the dev_d*() API wrappers.