omap2+: Remove useless Makefile line

Commit f41caddb ("omap2+: Use Kconfig
symbol in Makefile instead of obj-y") reorganized this Makefile. But,
for some reason, it also added references to CONFIG_MACH_ENCORE and
board-omap3encore.o. But there's no Kconfig symbol MACH_ENCORE and
there's no file board-omap3encore.c. This line can safely be removed.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/Makefile

@@ -229,7 +229,6 @@ obj-$(CONFIG_MACH_DEVKIT8000)     	+= board-devkit8000.o
 obj-$(CONFIG_MACH_OMAP_LDP)		+= board-ldp.o
 obj-$(CONFIG_MACH_OMAP3530_LV_SOM)      += board-omap3logic.o
 obj-$(CONFIG_MACH_OMAP3_TORPEDO)        += board-omap3logic.o
-obj-$(CONFIG_MACH_ENCORE)		+= board-omap3encore.o
 obj-$(CONFIG_MACH_OVERO)		+= board-overo.o
 obj-$(CONFIG_MACH_OMAP3EVM)		+= board-omap3evm.o
 obj-$(CONFIG_MACH_OMAP3_PANDORA)	+= board-omap3pandora.o