mvpp2: Fix warning over 32bit vs 64bit targets

When we have a driver that is used on both 32bit and 64bit targets and
we are talking about address space we cannot use u64 nor u32 and instead
need to use phys_addr_t.

Fixes: 377883f16d36 ("net: mvpp2x: fix phy connected to wrong mdio issue")
Cc: Stefan Chulski <stefanc@marvell.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>

drivers/net/mvpp2.c

@@ -4722,7 +4722,7 @@ static int phy_info_parse(struct udevice *dev, struct mvpp2_port *port)
 	u32 id;
 	u32 phyaddr = 0;
 	int phy_mode = -1;
-	u64 mdio_addr;
+	phys_addr_t mdio_addr;
 
 	phy_node = fdtdec_lookup_phandle(gd->fdt_blob, port_node, "phy");