eCryptfs: collapse flag set into one statement

Andrew Morton wrote:
> > +     crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
> > +     crypt_stat->flags |= ECRYPTFS_KEY_VALID;
>
> Maybe the compiler can optimise those two statements, but we'd
> normally provide it with some manual help.

This patch provides the compiler with some manual help for
optimizing the setting of some flags.

Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>