[SCSI] lpfc 8.1.1 : Adjust use of scsi_block_requests and interaction w/ FC transport

- Remove unnecessary scsi_block_requests calls on rport deletes.
  This was deadlocking the sdev removals as they wanted to flush commands.
- No longer block requests when adding the remote port (to block
  discovery). Instead, register, then change port role. Maps to Qlogic
  behavior, and closer to the register-node-upon-first-ELS behavior.

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