cifs NTLMv2/NTLMSSP Change variable name mac_key to session key to reflect the key it holds

Change name of variable mac_key to session key.
The reason mac_key was changed to session key is, this structure does not
hold message authentication code, it holds the session key (for ntlmv2,
ntlmv1 etc.).  mac is generated as a signature in cifs_calc* functions.

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 0cdfb8c..14dfa9a 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -97,7 +97,7 @@
 	/* Netbios frames protocol not supported at this time */
 };
 
-struct mac_key {
+struct session_key {
 	unsigned int len;
 	union {
 		char ntlm[CIFS_SESS_KEY_SIZE + 16];
@@ -182,7 +182,7 @@
 	/* 16th byte of RFC1001 workstation name is always null */
 	char workstation_RFC1001_name[RFC1001_NAME_LEN_WITH_NULL];
 	__u32 sequence_number; /* needed for CIFS PDU signature */
-	struct mac_key mac_signing_key;
+	struct session_key session_key;
 	char ntlmv2_hash[16];
 	unsigned long lstrp; /* when we got last response from this server */
 	u16 dialect; /* dialect index that server chose */