net: sched: Return the correct errno code

When kalloc or kmemdup failed, should return ENOMEM rather than ENOBUF.

Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Link: https://lore.kernel.org/r/20210204073950.18372-1-zhengyongjun3@huawei.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>