CVE-2022-50245 rapidio: fix possible UAF when kfifo_alloc() fails

In the Linux kernel, the following vulnerability has been resolved: rapidio: fix possible UAF when kfifoalloc fails If kfifoalloc fails in mportcdevopen, goto errfifo and just free priv. But priv is still in the chdev-filelist, then list traversal may cause UAF. This fixes the following smatch...