Currently we claim that omap4-panda and omap4-panda-es are essentially
the same, but they are not since PandaBoard-ES uses OMAP4460 and
PandaBoard uses OMAP4430.

So, split the common definition and make the model name available.
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>