mx51evk: Fix build error when CONFIG_VIDEO is disabled

The inclusion of LCD patch into mx51evk breaks the build when
CONFIG_VIDEO is disabled. Fix this by splitting the video related
stuff to a new file.

Also rename the function lcd_iomux to setup_iomux_lcd to make the
namings aligned with the other iomux functions.

Signed-off-by: Vikram Narayanan <vikram186@gmail.com>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
diff --git a/board/freescale/mx51evk/Makefile b/board/freescale/mx51evk/Makefile
index 224eaa3..2310fe1 100644
--- a/board/freescale/mx51evk/Makefile
+++ b/board/freescale/mx51evk/Makefile
@@ -23,8 +23,10 @@
 
 LIB	= $(obj)lib$(BOARD).o
 
-COBJS	:= mx51evk.o
+COBJS-y			+= mx51evk.o
+COBJS-$(CONFIG_VIDEO)	+= mx51evk_video.o
 
+COBJS	:= $(COBJS-y)
 SRCS	:= $(COBJS:.o=.c)
 OBJS	:= $(addprefix $(obj),$(COBJS))