benet: fix BUG when creating VFs

benet crashes as soon as SRIOV VFs are created:

kernel BUG at mm/vmalloc.c:3457!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 4 UID: 0 PID: 7408 Comm: test.sh Kdump: loaded Not tainted 6.16.0+ #1 PREEMPT(voluntary)
[...]
RIP: 0010:vunmap+0x5f/0x70
[...]
Call Trace:
<TASK>
__iommu_dma_free+0xe8/0x1c0
be_cmd_set_mac_list+0x3fe/0x640 [be2net]
be_cmd_set_mac+0xaf/0x110 [be2net]
be_vf_eth_addr_config+0x19f/0x330 [be2net]
be_vf_setup+0x4f7/0x990 [be2net]
be_pci_sriov_configure+0x3a1/0x470 [be2net]
sriov_numvfs_store+0x20b/0x380
kernfs_fop_write_iter+0x354/0x530
vfs_write+0x9b9/0xf60
ksys_write+0xf3/0x1d0
do_syscall_64+0x8c/0x3d0

be_cmd_set_mac_list() calls dma_free_coherent() under a spin_lock_bh.
Fix it by freeing only after the lock has been released.

Fixes: 1a82d19ca2d6 ("be2net: fix sleeping while atomic bugs in be_ndo_bridge_getlink")
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20250801101338.72502-1-mschmidt@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>