mei: rename enum mei_cb_major_types to enum mei_cb_file_ops

1. Rename mei_cb_major_types to more understandable mei_cb_file_ops
2. Rename member struct mei_cl_cb of this type to simple 'fop_type'
3. Add kernel doc for the type

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/misc/mei/init.c b/drivers/misc/mei/init.c
index 0046ca5..85b6520 100644
--- a/drivers/misc/mei/init.c
+++ b/drivers/misc/mei/init.c
@@ -597,7 +597,7 @@
 	if (!cb)
 		return -ENOMEM;
 
-	cb->major_file_operations = MEI_CLOSE;
+	cb->fop_type = MEI_FOP_CLOSE;
 	if (dev->mei_host_buffer_is_empty) {
 		dev->mei_host_buffer_is_empty = false;
 		if (mei_disconnect(dev, cl)) {