net: hisilicon: hns: Remove unused hns_rcb_start

hns_rcb_start() has been unused since 2016's
commit 454784d8 ("net: hns: delete redundancy ring enable operations")

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Jijie <Shao&lt;shaojijie@huawei.com>
Link: https://patch.msgid.link/20241218163341.40297-3-linux@treblig.org


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