drivers: net: davinci_mdio: Use of_device_get_match_data()

Use the more modern API to get the match data out of the of match table.
This saves some code, lines, and nicely avoids referencing the match
table when it is undefined with configurations where CONFIG_OF=n.

Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: <linux-omap@vger.kernel.org>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210123034428.2841052-3-swboyd@chromium.org