eth: fbnic: fix saving stats from XDP_TX rings on close

eth: fbnic: fix saving stats from XDP_TX rings on close

When rings are freed - stats get added to the device level stat
structs. Save the stats from the XDP_TX ring just as Tx stats.
Previously they would be saved to Rx and Tx stats. So we'd not
see XDP_TX packets as Rx during runtime but after an down/up cycle
the packets would appear in stats.

Correct the helper used by ethtool code which does a runtime
config switch.

Reviewed-by: Simon Horman <horms@kernel.org>
Fixes: 5213ff086344 ("eth: fbnic: Collect packet statistics for XDP")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20251007232653.2099376-4-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>