[SCSI] fc transport: add fc_host system_hostname attribute and u64_to_wwn()

This patch updates the fc transport for the following:

- Addition of a new attribute "system_hostname" which can be
  used to set the fully qualified hostname that the fc_host
  is attached to. The fc_host can then register this string
  as the FDMI-based host name attribute.
  Note: for NPIV, a fc_host could be associated with a system which
    is not the local system.

- Add the inline function u64_to_wwn(), which is the inverse of the
  existing wwn_to_u64() function.

- Slight reorg, just to keep dynamic attributes with each other, etc

Signed-off-by: James Smart <James.Smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>