eth: fbnic: take netif_addr_lock_bh() around rx mode address programming

eth: fbnic: take netif_addr_lock_bh() around rx mode address programming

When __fbnic_set_rx_mode() is called from contexts other than
.ndo_set_rx_mode_async(), the uc and mc addr lists are accessed
without the addr lock that __hw_addr_sync_dev() and
__hw_addr_unsync_dev() require. Wrap these unprotected accesses with
netif_addr_lock_bh(). fbnic_clear_rx_mode() has similar issues.

Fixes: eb690ef8d1c2 ("eth: fbnic: Add L2 address programming")
Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260617-linux-fbnic-hwaddr-v1-1-3f9f5dee7f99@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>