Mlo flag of vdev is set in wlan_hdd_cfg80211_start_bss context which
happens before pe session creation, so we may get a mlo vdev but the
pe session is not created.
Check link session Before populate MLO RNR IE.
Change-Id: I59da17bf1722c5a580c804ec8e6bf801aa510b0a
CRs-Fixed: 3105243