[SCSI] mpt fusion: Link speed change display support

When there is state change in FC links, a message is displayed with
old and new link speed.

signed-off-by: Sathya Prakash <sathya.prakash@lsi.com>
Acked-by: Eric Moore <Eric.Moore@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>