qcacld-2.0: Add string length validation

In hdd_parse_get_ibss_peer_info(), issue is reported by external
researcher that lack of string length validation might lead to
out-of-bounds read.
Related string length validation is added accordingly.

Change-Id: If04cc77b5fca782094dc577b21e1537dfe783282
CRs-Fixed: 2101686