ARM: davinci: da8xx boards: gpio device creation

Register  gpio platform device on DA8XX boards.

While at it, group related include files together.

Signed-off-by: Philip Avinash <avinashphilip@ti.com>
[nsekhar@ti.com: remove SoC specific parts from this file.
		 fix compile warnings]
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>