[CIFS] clean up server protocol handling

We're currently declaring both a sockaddr_in and sockaddr6_in on the
stack, but we really only need storage for one of them. Declare a
sockaddr struct and cast it to the proper type. Also, eliminate the
protocolType field in the TCP_Server_Info struct. It's redundant since
we have a sa_family field in the sockaddr anyway.

We may need to revisit this if SCTP is ever implemented, but for now
this will simplify the code.

CIFS over IPv6 also has a number of problems currently. This fixes all
of them that I found. Eventually, it would be nice to move more of the
code to be protocol independent, but this is a start.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifs_spnego.c b/fs/cifs/cifs_spnego.c
index fcee929..0ab2fb5 100644
--- a/fs/cifs/cifs_spnego.c
+++ b/fs/cifs/cifs_spnego.c
@@ -73,8 +73,8 @@
  * strlen(";sec=ntlmsspi") */
 #define MAX_MECH_STR_LEN	13
 
-/* max possible addr len eg FEDC:BA98:7654:3210:FEDC:BA98:7654:3210/60 */
-#define MAX_IPV6_ADDR_LEN	42
+/* max possible addr len eg FEDC:BA98:7654:3210:FEDC:BA98:7654:3210/128 */
+#define MAX_IPV6_ADDR_LEN	43
 
 /* strlen of "host=" */
 #define HOST_KEY_LEN		5