Fix error message and adds information to config

This patch fixes a typo in an error message and add some
information to the checksum verification option.

src/stream-tcp.c

@@ -2784,7 +2784,7 @@ int StreamTcpValidateChecksum(Packet *p)
 
     if (p->tcpc.comp_csum != p->tcph->th_sum) {
         ret = 0;
-        SCLogDebug("Checksum of recevied packet %p is invalid",p);
+        SCLogDebug("Checksum of received packet %p is invalid",p);
     }
 
     return ret;

suricata.yaml

@@ -327,6 +327,9 @@ flow-timeouts:
                                 # packet. If csum validation is specified as
                                 # "yes", then packet with invalid csum will not
                                 # be processed by the engine stream/app layer.
+                                # Warning: locally generated trafic can be
+                                # generated without checksum due to hardware offload
+                                # of checksum
 #   max_sessions: 262144        # 256k concurrent sessions
 #   prealloc_sessions: 32768    # 32k sessions prealloc'd
 #   midstream: false            # don't allow midstream session pickups