qcacld-3.0: Convert wlan_hdd_ext_scan.c to unified logging

Currently the HDD code uses a variety of logging APIs.  In
qcacld-3.0 HDD should converge on a unified set of logging APIs.
Update wlan_hdd_ext_scan.c to use the unified set of APIs.

Change-Id: I2777678a6d85d0d7c87b37144219cf18dc5c7d3d
CRs-Fixed: 937650