mei: don't update offset in write

commit a103af1b upstream.

MEI enables writes of complete messages only
while read can be performed in parts, hence
write should not update the file offset to
not break interleaving partial reads with writes.

Cc: <stable@vger.kernel.org>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/main.c

@@ -304,7 +304,6 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
 		goto out;
 	}
 
-	*offset = 0;
 	cb = mei_cl_alloc_cb(cl, length, MEI_FOP_WRITE, file);
 	if (!cb) {
 		rets = -ENOMEM;