cifs: remove set but not used variables

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

fs/cifs/file.c: In function cifs_lock:
fs/cifs/file.c:1696:24: warning: variable cinode set but not used [-Wunused-but-set-variable]
fs/cifs/file.c: In function cifs_write:
fs/cifs/file.c:1765:23: warning: variable cifs_sb set but not used [-Wunused-but-set-variable]
fs/cifs/file.c: In function collect_uncached_read_data:
fs/cifs/file.c:3578:20: warning: variable tcon set but not used [-Wunused-but-set-variable]

'cinode' is never used since introduced by
commit 03776f45 ("CIFS: Simplify byte range locking code")
'cifs_sb' is not used since commit cb7e9eab ("CIFS: Use
multicredits for SMB 2.1/3 writes").
'tcon' is not used since commit d26e2903 ("smb3: fix bytes_read statistics")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/file.c

@@ -1693,7 +1693,6 @@ int cifs_lock(struct file *file, int cmd, struct file_lock *flock)
 	bool posix_lck = false;
 	struct cifs_sb_info *cifs_sb;
 	struct cifs_tcon *tcon;
-	struct cifsInodeInfo *cinode;
 	struct cifsFileInfo *cfile;
 	__u32 type;
 
@@ -1710,7 +1709,6 @@ int cifs_lock(struct file *file, int cmd, struct file_lock *flock)
 	cifs_read_flock(flock, &type, &lock, &unlock, &wait_flag,
 			tcon->ses->server);
 	cifs_sb = CIFS_FILE_SB(file);
-	cinode = CIFS_I(file_inode(file));
 
 	if (cap_unix(tcon->ses) &&
 	    (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
@@ -1762,7 +1760,6 @@ cifs_write(struct cifsFileInfo *open_file, __u32 pid, const char *write_data,
 	int rc = 0;
 	unsigned int bytes_written = 0;
 	unsigned int total_written;
-	struct cifs_sb_info *cifs_sb;
 	struct cifs_tcon *tcon;
 	struct TCP_Server_Info *server;
 	unsigned int xid;
@@ -1770,8 +1767,6 @@ cifs_write(struct cifsFileInfo *open_file, __u32 pid, const char *write_data,
 	struct cifsInodeInfo *cifsi = CIFS_I(d_inode(dentry));
 	struct cifs_io_parms io_parms;
 
-	cifs_sb = CIFS_SB(dentry->d_sb);
-
 	cifs_dbg(FYI, "write %zd bytes to offset %lld of %pd\n",
 		 write_size, *offset, dentry);
 
@@ -3575,10 +3570,8 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx)
 	struct cifs_readdata *rdata, *tmp;
 	struct iov_iter *to = &ctx->iter;
 	struct cifs_sb_info *cifs_sb;
-	struct cifs_tcon *tcon;
 	int rc;
 
-	tcon = tlink_tcon(ctx->cfile->tlink);
 	cifs_sb = CIFS_SB(ctx->cfile->dentry->d_sb);
 
 	mutex_lock(&ctx->aio_mutex);