qed: fix division by zero in qed_init_wfq_param when all vports are configured

qed: fix division by zero in qed_init_wfq_param when all vports are configured

In qed_init_wfq_param(), variable non_requested_count can become zero
when the number of vports with the configured flag set (including the
current vport being configured) equals total num_vports. This happens
when configuring the last unconfigured vport or when re-configuring
an already configured vport.

The function then calculates left_rate_per_vp = total_left_rate /
non_requested_count, which causes division by zero.

Fix this by skipping the division when non_requested_count is zero.
In that case, there is no remaining bandwidth to distribute, so just
record the configuration for the current vport and return success.

Fixes: bcd197c81f63 ("qed: Add vport WFQ configuration APIs")
Signed-off-by: Evgenii Burenchev <evg28bur@yandex.ru>
Link: https://patch.msgid.link/20260507145520.23106-1-evg28bur@yandex.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>