ndctl: release v55

This release incorporates the capabilities of the 4.9 kernel. Major
highlights include support for retrieving the health status of HPE
NVDIMMs, and new label manipulation / validation commands.

Commands:
    list: add HPE NVDIMM health reporting
    init-labels: initialize a namespace-label index-block
    check-labels: validate a namespace-label index-block
    create-namespace: fix crash when target region disabled
    bash-completion: add {en,dis}able-dimm and {check,init}-labels support

Tests:
    dsm-fail: check that namespaces stay disabled when label DSMs fail
    multi-pmem: validate pmem-region sub-division support
    libndctl: add btt-size check
    libndctl: test health event notification support
    device-dax: validate "invalidate on shutdown" behavior of dax devices
    device-dax: validate direct-i/o to device-dax mappings
    device-dax: check kernel fix for file offset to phys offset translation
    device-dax: check kernel fix for crash when reading /proc/<pid>/smaps
    clear: check kernel fix for making cleared badblocks stay cleared

Apis:
    daxctl_region_get_available_size: new, in support of dax sub-division
    daxctl_region_get_devname: new, in support of dax sub-division
    daxctl_region_get_dev_seed: new, in support of dax sub-division
    ndctl_dimm_get_health_eventfd: new, fires upon firmware health event notification
    ndctl_cmd_cfg_read_get_size: new, simplifies label manipulation routines
    ndctl_dimm_get_available_labels: fix error return value to be ULONG_MAX
    ndctl_region_get_available_size: fix error return value to be ULLONG_MAX
    ndctl_dimm_cmd_new_cfg_{read,write}: fix to not overflow label area size