Without WLAN we cannot switch omap4 to use device tree
only booting. This patch can be reverted when the
binding for wl12xx is added.

Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Rajendra Nayak <rnayak@ti.com>
Cc: devicetree-discuss@lists.ozlabs.org
Tested-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>