net: stmmac: dwc-qos: name struct plat_stmmacenet_data consistently

Most of the stmmac driver uses "plat_dat" to name the platform data,
and "data" is used for the glue driver data. make dwc-qos follow
this pattern to avoid silly mistakes.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Thierry Reding <treding@nvidia.com>
Link: https://patch.msgid.link/E1tmbhe-004vSt-M3@rmk-PC.armlinux.org.uk


Signed-off-by: Jakub Kicinski <kuba@kernel.org>