net: stmmac: move initialisation of dma_cfg->atds

net: stmmac: move initialisation of dma_cfg->atds

Move the initialisation of priv->plat->dma_cfg->atds, which indicates
that 8 32-bit word descriptors are being used for pre-v4.0 cores, after
the call to stmmac_hwif_init(), which will initialise priv->extend_desc
and priv->mode (the descriptor mode.)

We don't need to re-evaluate this in stmmac_init_dma_engine() - as the
state that it depends on only changes in stmmac_hwif_init() which is
only called in the probe path. Also, once set, no code clears this
flag.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vvuXt-0000000Avnc-0UYC@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>