[CIFS] Remove redundant test

In fs/cifs/cifssmb.c, pLockData is tested for being NULL at the beginning
of the function, and not reassigned subsequently.

A simplified version of the semantic patch that makes this change is as
follows: (http://www.emn.fr/x-info/coccinelle/)

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifssmb.c

@@ -1871,10 +1871,6 @@ CIFSSMBPosixLock(const int xid, struct cifsTconInfo *tcon,
 			rc = -EIO;      /* bad smb */
 			goto plk_err_exit;
 		}
-		if (pLockData == NULL) {
-			rc = -EINVAL;
-			goto plk_err_exit;
-		}
 		data_offset = le16_to_cpu(pSMBr->t2.DataOffset);
 		data_count  = le16_to_cpu(pSMBr->t2.DataCount);
 		if (data_count < sizeof(struct cifs_posix_lock)) {