wifihal: Fetch lowi caps again if not obtained

lowi server capabilities are fetched from fw
after lowi initialization and wifi is turned on.
When wifihal queries caps before wifi is on,
it will receive no capabilities. Hence wifihal
should retry for capabilites before sending
lowi request

CRs-Fixed: 2986700
Change-Id: Ic8871794dbdd2d0a876449eb8116bad6095257bc