ecryptfs: Make ecryptfs_xattr_handler static

Fix sparse warning:

fs/ecryptfs/inode.c:1138:28: warning:
 symbol 'ecryptfs_xattr_handler' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>

fs/ecryptfs/inode.c

@@ -1135,7 +1135,7 @@ static int ecryptfs_xattr_set(const struct xattr_handler *handler,
 	}
 }
 
-const struct xattr_handler ecryptfs_xattr_handler = {
+static const struct xattr_handler ecryptfs_xattr_handler = {
 	.prefix = "",  /* match anything */
 	.get = ecryptfs_xattr_get,
 	.set = ecryptfs_xattr_set,