CVE-2026-92494: ext4: fix buffer_head leak in ext4_init_orphan_info

In the Linux kernel, the following vulnerability has been resolved:

ext4: fix bufferhead leak in ext4initorphaninfo

ext4initorphaninfo() reads orphan file blocks with ext4bread() and stores the returned bufferhead in oi->ofbinfo[i].obbh.

If ext4bread() succeeds but the orphan block magic or checksum validation fails, the function jumps to outfree. However, the old outfree loop starts releasing buffers from i - 1, so the current bufferhead at index i is skipped.

This leaks the bufferhead reference obtained by ext4bread() on the bad magic and bad checksum error paths.

Fix this by tracking the number of successfully read bufferheads and releasing exactly those bufferheads on the error path.