rnbd-clt: check capacity inside rnbd_clt_change_capacity

Currently, process_msg_open_rsp checks if capacity changed or not before
call rnbd_clt_change_capacity while the checking also make sense for
rnbd_clt_resize_dev_store, let's move the checking into the function.

Acked-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Guoqing Jiang <guoqing.jiang@linux.dev>
Link: https://lore.kernel.org/r/20220706133152.12058-7-guoqing.jiang@linux.dev


Signed-off-by: Jens Axboe <axboe@kernel.dk>