qcacmn: Fix wlan_cfg file inclusion and remove duplicate static API

Due to issues in Kbuild wlan_cfg was included using relative path.
Also getting rid of a duplicate static function definition in
dp_peer.c.

Change-Id: Ie0883340a9143b739119f18c8871b4baa9787980
CRs-Fixed: 2005582

dp/wifi3.0/dp_main.c

@@ -28,8 +28,9 @@
 #include "dp_internal.h"
 #include "dp_tx.h"
 #include "dp_rx.h"
-#include "../../wlan_cfg/wlan_cfg.h"
 #include <cdp_txrx_handle.h>
+#include <wlan_cfg.h>
+
 #define DP_INTR_POLL_TIMER_MS	100
 /**
  * dp_setup_srng - Internal function to setup SRNG rings used by data path