Add GPIO hwmod data for OMAP2420 and add the required
GPIO device attributes in the gpio header file

Also remove "omap24xx.h" header file as it is not required
anymore.
Signed-off-by: Charulatha V <charu@ti.com>
Acked-by: Benoit Cousson <b-cousson@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>