qcacld-3.0: Fix race condition in sending STA IPA offload enable

During resource unloading, if two next to next client connect
request comes, one is handled in pending event handler in
wlan_ipa_uc_op_cb callback after processing FW TX suspend response
and other one is handled in scheduler thread, this causes race
condition in sending IPA offload enable for STA iface. So send IPA
enable req to FW before queuing the client connect event to the
pending events.

Change-Id: Ifcabc2481e590e5e128434614c4b46fe53a34636
CRs-Fixed: 2460573