eth: fbnic: Fix tx_dropped reporting

Correctly copy the tx_dropped stats from the fbd->hw_stats to the
rtnl_link_stats64 struct.

Fixes: 5f8bd2ce ("eth: fbnic: add support for TMI stats")
Signed-off-by: Mohsin Bashir <mohsin.bashr@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250802024636.679317-2-mohsin.bashr@gmail.com


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