CVE-2026-53087: net: bcmgenet: fix leaking free_bds

In the Linux kernel, the following vulnerability has been resolved:

net: bcmgenet: fix leaking freebds

While reclaiming the tx queue we fast forward the write pointer to drop any data in flight. These dropped frames are not added back to the pool of free bds. We also need to tell the netdev that we are dropping said data.