Add an API to create a sequence of 802.11 element fragments, and
similarly, add an API to create a sequence of 802.11 subelement
fragments. Add an inline mode for both these APIs to carry out the
fragmentation within the source buffer in order to reduce buffer
requirements and to eliminate memory copies/moves for the lead
element/subelement. Conversely, add a non-inline mode to create the
fragment sequence in a separate buffer.
Add common helper functionality shared between these APIs.
CRs-Fixed: 3124099
Change-Id: I48ef6e529360ea40d58320327a50884bc1638689
b76c403d0e