net: stmmac: rearrange tc_init()

net: stmmac: rearrange tc_init()

To make future changes easier, rearrange the use of dma_cap->l3l4fnum
vs priv->flow_entries_max.

Always initialise priv->flow_entries_max from dma_cap->l3l4fnum, then
use priv->flow_entries_max to determine whether we allocate
priv->flow_entries and set it up.

This change is safe because tc_init() is only called once from
stmmac_dvr_probe().

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/E1v945Y-0000000Ameb-2gDI@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>