btrfs-progs: remove c++ protection from internal headers

We don't need the c++ name mangling protection in headers that are not
part of libbtrfs.

Signed-off-by: David Sterba <dsterba@suse.com>

common/rbtree-utils.h

@@ -21,10 +21,6 @@
 
 #include "kernel-lib/rbtree.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /* The common insert/search/free functions */
 typedef int (*rb_compare_nodes)(struct rb_node *node1, struct rb_node *node2);
 typedef int (*rb_compare_keys)(struct rb_node *node, void *key);
@@ -46,8 +42,4 @@ static void free_##name##_tree(struct rb_root *root)	\
 	rb_free_nodes(root, free_func);			\
 }
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif

kernel-lib/rbtree_augmented.h

@@ -26,10 +26,6 @@
 
 #include "kernel-lib/rbtree.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /*
  * Please note - only struct rb_augment_callbacks and the prototypes for
  * rb_insert_augmented() and rb_erase_augmented() are intended to be public.
@@ -242,8 +238,4 @@ rb_erase_augmented(struct rb_node *node, struct rb_root *root,
 		__rb_erase_color(rebalance, root, augment->rotate);
 }
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif	/* _LINUX_RBTREE_AUGMENTED_H */