nfsd4: move rq_flavor into svc_cred

Move the rq_flavor into struct svc_cred, and use it in setclientid and
exchange_id comparisons as well.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c
index 79717a4..b42eaf3 100644
--- a/fs/nfsd/auth.c
+++ b/fs/nfsd/auth.c
@@ -10,7 +10,7 @@
 	struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;
 
 	for (f = exp->ex_flavors; f < end; f++) {
-		if (f->pseudoflavor == rqstp->rq_flavor)
+		if (f->pseudoflavor == rqstp->rq_cred.cr_flavor)
 			return f->flags;
 	}
 	return exp->ex_flags;