omap: Remap L3, L4 to get more kernel io address space

This patch remap L3 and L4 io space to get more kernel address space.
With this patch, 512 MB of IO space is reclaimed.
Some more combinations are possible but to make it uniform across
OMAP24XX, OMAP34XX and OMAP4430, these io combinations are chosen

Once this is reviewed and tested sufficiently, a documentation entry can
be created to ease up reading and debugging.
Like "Documentation/arm/omap/io_map.txt"

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>