wlan: Initialize sw_pta before vos_open

bt_profile_state can be triggered before initializing sw_pta
which can cause accessing elements that are not initialized.

To address this issue initialize sw_pta before registering
bt_profile_state.

Change-Id: I3eebf2dfd03658ca89b11e7b0b4a07ba96d6dc82
CRs-Fixed: 2899060