qcacld-3.0: Add INI parameter to set the value for packet capture mode

pktcapture_mode - Control to set pktcapture mode

This ini is used to set pktcapture mode only if packet capture mode
is enabled.

0 - default (stop packet capture)
1 - Capture Mgmt packets
2 - Capture Data packets
3 - Capture both Mgmt and Data packets

Change-Id: Ic4133f8d4f65fb86158916c90bd453c3f1c3355d
CRs-Fixed: 2448546