MFV r272500:

Don't inherit flags other than DS_FLAG_CI_DATASET and DS_FLAG_INCONSISTENT
when cloning.  This prevents DS_FLAG_DEFER_DESTROY being inherited from a
clone that is marked for deferred destroy, which causes snapshots of the
clone being destroyed when getting a hold or clone.

Illumos issue:
    5150 zfs clone of a defer_destroy snapshot causes strangeness

MFC after:	1 week
MFV r272501:

Illumos issue:
    5177 remove dead code from dsl_scan.c

MFC after:	2 weeks
Minor code styling.

Suggested by:	glebius @
devfs: don't take proctree_lock unconditionally in devfs_close

MFC after:	1 week
Fix length of Extended INQUIRY Data VPD page.

MFC after:	3 days
MFV r272585:

Split the godfather zio into CPU number's to reduce lock
contention.

Illumos issue:
    5176 lock contention on godfather zio

MFC after:	2 weeks
MFV r272588:

Handle old format deadlist.

Illumos issue:
    5178 zdb -vvvvv on old-format pool fails in dump_deadlist()

MFC after:	2 weeks
devfs: tidy up after 272596

This moves a var to an if statement, no functional changes.

MFC after:	1 week
MFV r272591:

Use loaned ARC buffer for zfs receive to avoid copy.

Illumos issue:
    5162 zfs recv should use loaned arc buffer to avoid copy

MFC after:	2 weeks
Use documented compat string for msm uart.
Whilst here use tab instead of spaces.

Approved by:    stas (mentor)
Disable generating vfp and NEON instructions in the arm kernel.