Fix read issue detected by the following Python program. The issue was that the caller's buffer pointer was not being advanced between segments of the read data.

Signed-off-by: lpleahy

-----  UnbufferedRead.py  -----

import httplib
conn = httplib.HTTPConnection("10.241.97.30")
conn.request('GET', '/')
resp = conn.getresponse(buffering=True)
if resp.status != 200:
   print "status:", resp.status
   print "aborting"
   sys.exit(1)
while True:
   chunk = resp.read()
   if not chunk:
       break
   print chunk


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13077 6f19259b-4bc3-4df7-8a09-765794883524

StdLib/EfiSocketLib/Tcp4.c

@@ -1571,6 +1571,11 @@ EslTcp4Receive (
             DataLength ));
   CopyMem ( pBuffer, pPacket->pBuffer, DataLength );
 
+  //
+  //  Set the next buffer address
+  //
+  pBuffer += DataLength;
+
   //
   //  Determine if the data is being read
   //

StdLib/EfiSocketLib/Tcp6.c

@@ -1635,6 +1635,11 @@ EslTcp6Receive (
             DataLength ));
   CopyMem ( pBuffer, pPacket->pBuffer, DataLength );
 
+  //
+  //  Set the next buffer address
+  //
+  pBuffer += DataLength;
+
   //
   //  Determine if the data is being read
   //