class: rename "sem" to "class_sem" in internal class structure

This renames the struct class "sem" field to be "class_sem" to make
things easier when struct bus_type and struct class merge in the future.
It also makes grepping for fields easier as well.

Based on an idea from Kay.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/base/base.h b/drivers/base/base.h
index a77d4bd..4435732 100644
--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -45,7 +45,7 @@
  * @class_devices - list of devices associated with this class
  * @class_interfaces - list of class_interfaces associated with this class
  * @class_dirs -
- * @sem - semaphore to protect the children, devices, and interfaces lists.
+ * @class_sem - semaphore to protect the children, devices, and interfaces lists.
  * @class - pointer back to the struct class that this structure is associated
  * with.
  *
@@ -58,7 +58,7 @@
 	struct list_head class_devices;
 	struct list_head class_interfaces;
 	struct kset class_dirs;
-	struct semaphore sem;
+	struct semaphore class_sem;
 	struct class *class;
 };
 #define to_class(obj)	\