net: ti: icssg: Remove dedicated workqueue for ndo_set_rx_mode callback

net: ti: icssg: Remove dedicated workqueue for ndo_set_rx_mode callback

Currently, both the icssg-prueth and icssg-prueth-sr1 drivers create
a dedicated 'emac->cmd_wq' workqueue.

In the icssg-prueth-sr1 driver, this workqueue is not utilized at all.

In the icssg-prueth driver, the workqueue is only used to execute the
actual processing of ndo_set_rx_mode. However, creating a dedicated
workqueue for such a simple use case is unnecessary. To simplify the
code, switch to using the system default workqueue instead.

Signed-off-by: Kevin Hao <haokexin@gmail.com>
Tested-by: Meghana Malladi <m-malladi@ti.com>
Reviewed-by: MD Danish Anwar <danishanwar@ti.com>
Link: https://patch.msgid.link/20260205-icssg-prueth-workqueue-v2-1-cf5cf97efb37@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>