nimble/ll: Fix verifying incomplete data when enabling periodic adv
nimble/ll: Fix verifying incomplete data when enabling periodic adv

Properties were checked instead of flags. This was affecting
HCI/DDI/BI-13-C qualification test case,

apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble