net: dsa: Drop GPIO includes

Commit 52638f71 ("dsa: Move gpio reset into switch driver")
moved the GPIO handling into the switch drivers but forgot
to remove the GPIO header includes.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>