afs: Handle CONFIG_PROC_FS=n

afs: Handle CONFIG_PROC_FS=n

The AFS filesystem depends at the moment on /proc for configuration and
also presents information that way - however, this causes a compilation
failure if procfs is disabled.

Fix it so that the procfs bits aren't compiled in if procfs is disabled.

This means that you can't configure the AFS filesystem directly, but it is
still usable provided that an up-to-date keyutils is installed to look up
cells by SRV or AFSDB DNS records.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>