net: stmmac: dwc-qos-eth: use devm_kzalloc() for AXI data

Everywhere else in the driver uses devm_kzalloc() when allocating the
AXI data, so there is no kfree() of this structure. However,
dwc-qos-eth uses kzalloc(), which leads to this memory being leaked.
Switch to use devm_kzalloc().

Fixes: d8256121 ("stmmac: adding new glue driver dwmac-dwc-qos-eth")
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/E1tsRyv-0064nU-O9@rmk-PC.armlinux.org.uk


Signed-off-by: Paolo Abeni <pabeni@redhat.com>