Instead of looking up the dentry of an NCCI node again in
capifs_free_ncci pass the pointer via the capifs user.

This patch also reduces the #ifdef mess in capi.c a bit as far as capifs
was causing it.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>