ARM: OMAP2+: All OMAP2PLUS uses omap-device.o target so add one entry

All OMAP2PLUS based devices, builds omap-device.o target;
so just add one entry so that there is no need to patch this file
for any future OMAP2+ devices.

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>