fscrypt: properly declare on-stack completion

When a completion is declared on-stack we have to use
COMPLETION_INITIALIZER_ONSTACK().

Fixes: 0b81d07790726 ("fs crypto: move per-file encryption from f2fs
tree to fs/crypto")
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/crypto/fscrypt_private.h

@@ -86,7 +86,7 @@ struct fscrypt_completion_result {
 
 #define DECLARE_FS_COMPLETION_RESULT(ecr) \
 	struct fscrypt_completion_result ecr = { \
-		COMPLETION_INITIALIZER((ecr).completion), 0 }
+		COMPLETION_INITIALIZER_ONSTACK((ecr).completion), 0 }
 
 
 /* crypto.c */