scsi: lpfc: Update outdated comment for renamed lpfc_freenode()

scsi: lpfc: Update outdated comment for renamed lpfc_freenode()

The function lpfc_freenode() was renamed to lpfc_cleanup_node() by
commit 685f0bf7afe0 ("[SCSI] lpfc 8.1.12 : Collapse discovery lists to a
single node list"), and commit a70e63eee1c1 ("scsi: lpfc: Fix NPIV
Fabric Node reference counting") later removed the lpfc_unreg_rpi() call
from lpfc_cleanup_node().

Remove the now-inaccurate "called from lpfc_freenode()" sentence and
reflow the remaining comment text for lpfc_unreg_rpi().

Assisted-by: unnamed:deepseek-v3.2 coccinelle
Signed-off-by: Kexin Sun <kexinsun@smail.nju.edu.cn>
Link: https://patch.msgid.link/20260321105909.7804-1-kexinsun@smail.nju.edu.cn
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>