[RFC v3 0/1] nvme: add passthrough error logging opt-in

[Alan Adamson]

v3:
- Log a passthrough specific message that dumps CDW* contents.
- Enable/disable vis sysfs rather than debugfs.

v2:
- Included Pankaj Raghav's patch 'nvme: ignore starting sector while error logging for passthrough requests'
  with a couple changes.
- Moved error_logging flag to nvme_ctrl structure
- The entire nvme-debugfs.c does not need to be guarded by #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS.
- Use IS_ENABLED((CONFIG_NVME_ERROR_LOGGING_DEBUG_FS)) to determine if error logging should be
  initialized.
- Various other nits.