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>

arch/arm/plat-omap/Makefile

@@ -10,9 +10,7 @@ obj-n :=
 obj-  :=
 
 # omap_device support (OMAP2+ only at the moment)
-obj-$(CONFIG_ARCH_OMAP2) += omap_device.o
-obj-$(CONFIG_ARCH_OMAP3) += omap_device.o
-obj-$(CONFIG_ARCH_OMAP4) += omap_device.o
+obj-$(CONFIG_ARCH_OMAP2PLUS) += omap_device.o
 
 obj-$(CONFIG_OMAP_DM_TIMER) += dmtimer.o
 obj-$(CONFIG_OMAP_DEBUG_DEVICES) += debug-devices.o