Add support for nvme based devids

[don-brady]

Description

Adds a devid for nvme devices. This is very similar to how the other 'bus' (scsi|sata|usb) devids are generated. The devid resides in a name/value pair in the leaf vdevs in a zpool config.

Motivation and Context

The ZED logic uses the devid for matching devices for operations like auto-online. The device ID is also useful for matching a zfs device with devices seen by libudev.

How Has This Been Tested?

ztest
zfs test suite: functional/fault tests
manual testing, as in:

$ lsblk
NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda           8:0    0 111.8G  0 disk 
├─sda1        8:1    0   511M  0 part /boot/efi
├─sda2        8:2    0    16G  0 part [SWAP]
└─sda3        8:3    0  84.1G  0 part /
nvme0n1     259:0    0 238.5G  0 disk 

$ sudo zpool create expresso nvme0n1
$ sudo zdb -C expresso | grep -E "path|devid"
                path: '/dev/nvme0n1p1'
                devid: 'nvme-INTEL_SSDPEKKW256G7_BTPY722506V2256D-part1'
                phys_path: 'pci-0000:3c:00.0-nvme-1'

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the ZFS on Linux code style requirements.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.
• All commit messages are properly formatted and contain Signed-off-by.
• Change has been approved by a ZFS on Linux member.

[codecov]

Codecov Report

Merging #7356 into master will decrease coverage by 0.03%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #7356      +/-   ##
==========================================
- Coverage   76.28%   76.25%   -0.04%     
==========================================
  Files         329      329              
  Lines      104191   104193       +2     
==========================================
- Hits        79483    79453      -30     
- Misses      24708    24740      +32

Flag	Coverage Δ
#kernel	76.04% <ø> (-0.19%)	⬇️
#user	65.47% <100%> (-0.16%)	⬇️

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