benet: fix BUG when creating VFs

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

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.