wifi: Add provision to create/remove dynamic interface(s).

This commit does following:
 - Add/Remove softap interface at runtime, if needed.
 - Use wlan.concurrent.interface as default softap interface.
 - Add build time support to enable SAP+SAP feature using
   QC_WIFI_HIDL_FEATURE_DUAL_AP flag. if enabled use wlan.interface
   as second SAP interface.

Change-Id: Icde3d54eda0f142e20f33cdb7ed95152eeee0bec
CRs-Fixed: 2257197