ARM: ux500: Move board specific GPIO info out to subordinate DTS files

GPIO numbers for the newly created gpio-regulator will differ from
board to board. Therefore it's not sensible to leave this information
in the top level DTSI file. Let's move them out to the DTS files
where they can correctly vary.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>