ARM: OMAP: Add 3430 gpio support

This patch adds 3430 gpio support.

It also contains a fix by Paul Walmsley <paul@pwsan.com> to use the
correct clock names for OMAP3430.

Signed-off-by: Syed Mohammed Khasim <x0khasim@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>