qcacld-3.0: Remove unused linux header file

Remove unused linux header file in packet capture component.

Change-Id: I668061d0a6516cca51a153e3713e8c0a5634fb64
CRs-Fixed: 3019885

components/pkt_capture/core/src/wlan_pkt_capture_mon_thread.c

@@ -21,7 +21,6 @@
  */
 
 #include "wlan_pkt_capture_mon_thread.h"
-#include <linux/kthread.h>
 #include "cds_ieee80211_common.h"
 #include "wlan_mgmt_txrx_utils_api.h"
 #include "cdp_txrx_ctrl.h"