qcacmn: os_if: Replace explicit comparison to NULL

Per the Linux Kernel coding style, as enforced by the kernel
checkpatch script, pointers should not be explicitly compared to
NULL. Therefore within os_if replace any such comparisons with logical
operations performed on the pointer itself.

Change-Id: I1cf6f897d1d2722d112dd3f802d789652373eaed
CRs-Fixed: 2418254

os_if/linux/wifi_pos/src/os_if_wifi_pos.c

@@ -54,7 +54,7 @@ static void os_if_wifi_pos_send_rsp(uint32_t pid, uint32_t rsp_msg_type,
 	}
 
 	skb = alloc_skb(NLMSG_SPACE(sizeof(tAniMsgHdr) + buf_len), GFP_ATOMIC);
-	if (skb == NULL) {
+	if (!skb) {
 		cfg80211_alert("alloc_skb failed");
 		return;
 	}