qcacld-3.0: Avoid use after free for SAP dev

There is a race between regulatory callback from restart SAP and
user space deleting the SAP dev, which can result into access of a
free adapter.

To avoid the above issue the SAP dev should be held before it gets
delete and release after the operation on SAP dev gets complete.

Change-Id: Idf7fc2adeb74ac62d2a63d8bc3ae0b1a0568693c
CRs-Fixed: 2789448