dpaa2-eth: use the correct software annotation field

The incorrect software annotation field was being used, swa->sg.sgt_size
instead of swa->tso.sgt_size, which meant that the SGT buffer was
unmapped with a wrong size.
This is also confirmed by the DMA API debug prints which showed the
following:

[   38.962434] DMA-API: fsl_dpaa2_eth dpni.2: device driver frees DMA memory with different size [device address=0x0000fffffafba740] [map size=224 bytes] [unmap size=0 bytes]
[   38.980496] WARNING: CPU: 11 PID: 1131 at kernel/dma/debug.c:973 check_unmap+0x58c/0x9b0
[   38.988586] Modules linked in:
[   38.991631] CPU: 11 PID: 1131 Comm: iperf3 Not tainted 5.18.0-rc7-00117-g59130eeb2b8f #1972
[   38.999970] Hardware name: NXP Layerscape LX2160ARDB (DT)

Fixes: 3dc709e0 ("dpaa2-eth: add support for software TSO")
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>