eth: fbnic: report software Tx queue stats

Gather and report software Tx queue stats - checksum stats
and queue stop / start.

Acked-by: Joe Damato <jdamato@fastly.com>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://patch.msgid.link/20250211181356.580800-5-kuba@kernel.org


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