ARM: w1-gpio: fix erroneous gpio requests

Fix regression introduced by commit d2323cf7

 ("onewire: w1-gpio: add
ext_pullup_enable pin in platform data") which added a gpio entry to the
platform data, but did not add the required initialisers to the board
files using it. Consequently, the driver would request gpio 0 at probe,
which could break other uses of the corresponding pin.

On AT91 requesting gpio 0 changes the pin muxing for PIOA0, which, for
instance, breaks SPI0 on at91sam9g20.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>