cifs: remove set but not used variable 'smb_buf'

Fixes gcc '-Wunused-but-set-variable' warning:

fs/cifs/sess.c: In function '_sess_auth_rawntlmssp_assemble_req':
fs/cifs/sess.c:1157:18: warning:
 variable 'smb_buf' set but not used [-Wunused-but-set-variable]

It never used since commit cc87c47d ("cifs: Separate rawntlmssp auth
from CIFS_SessSetup()")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/sess.c

@@ -1154,14 +1154,12 @@ sess_auth_kerberos(struct sess_data *sess_data)
 static int
 _sess_auth_rawntlmssp_assemble_req(struct sess_data *sess_data)
 {
-	struct smb_hdr *smb_buf;
 	SESSION_SETUP_ANDX *pSMB;
 	struct cifs_ses *ses = sess_data->ses;
 	__u32 capabilities;
 	char *bcc_ptr;
 
 	pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
-	smb_buf = (struct smb_hdr *)pSMB;
 
 	capabilities = cifs_ssetup_hdr(ses, pSMB);
 	if ((pSMB->req.hdr.Flags2 & SMBFLG2_UNICODE) == 0) {