qcacmn: Rate limit error logs from send_diag_netlink_data

Introduce proper logging APIs for diag module and also rate limit error
logs when skb allocation fails in low memory conditions to avoid excessive
logging side effects

Change-Id: Ia41ff7cfd526180825df61a43f1f59163947f257
CRs-Fixed: 2836681

utils/fwlog/dbglog_host.c

@@ -1750,8 +1750,7 @@ send_diag_netlink_data(const uint8_t *buffer, uint32_t len, uint32_t cmd)
 
 		skb_out = nlmsg_new(slot_len, GFP_ATOMIC);
 		if (!skb_out) {
-			AR_DEBUG_PRINTF(ATH_DEBUG_ERR,
-					("Failed to allocate new skb\n"));
+			diag_err_rl("Failed to allocate new skb");
 			return A_ERROR;
 		}