Backport: proc: make proc_fd_permission() thread-friendly

The upstream patch cannot be directly applied, since for us the fd related
functions still live in the base.c.

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=96d0df79f2644fc823f26c06491e182d87a90c2a

Change-Id: Ib617167a74a6c9415b0fd1639e2d19f523490074
1 file changed