Replace broken rbtree stubs with the real implementation from
lib/rbtree.c. The previous stubs had critical bugs:
- rb_link_node() only did *(rb_link) = node without initializing
rb_left and rb_right to NULL, causing crashes when traversing
the extent status tree
- rb_next/rb_prev were wrong (just returned right/left child)
- rb_insert_color was a no-op, breaking tree balancing
Include <linux/rbtree.h> and remove the conflicting struct definitions
and broken operation macros.
Co-developed-by: Claude <noreply@anthropic.com>
Signed-off-by: Simon Glass <simon.glass@canonical.com>
4b583a0eaa