lockdep: fixup the inode dir annotation

A slight oversight tripped lockdep debugging code, each lockdep
class should have but a single init site.

Rearange the code to make this true.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>