FSL: Convert board/freescale/common/Makefile to use CONFIG_

Convert the board/freescale/common/Makefile to use
CONFIG_* options to select which files to conditionally
compile into the board/freescale/common library rather
than conditionally compiling entire files.

Now handles::
    CONFIG_FSL_PIXIS
    CONFIG_FSL_DIU_FB
    CONFIG_PQ_MDS_PIB

CONFIG_ID_EEPROM is introduced until CFG_ID_EEPROM is gone.

Signed-off-by: Jon Loeliger <jdl@freescale.com>
diff --git a/board/freescale/mpc8610hpcd/Makefile b/board/freescale/mpc8610hpcd/Makefile
index 76087c1..12a92ae 100644
--- a/board/freescale/mpc8610hpcd/Makefile
+++ b/board/freescale/mpc8610hpcd/Makefile
@@ -27,14 +27,14 @@
 
 LIB	= $(obj)lib$(BOARD).a
 
-COBJS	:= $(BOARD).o \
-	../common/sys_eeprom.o \
-	../common/pixis.o \
-	mpc8610hpcd_diu.o \
-	../common/fsl_diu_fb.o
-
 SOBJS	:= init.o
 
+COBJS	:= $(BOARD).o
+
+COBJS-${CONFIG_FSL_DIU_FB}	+= mpc8610hpcd_diu.o
+
+COBJS	+= ${COBJS-y}
+
 SRCS	:= $(SOBJS:.o=.S) $(COBJS:.o=.c)
 OBJS	:= $(addprefix $(obj),$(COBJS))
 SOBJS	:= $(addprefix $(obj),$(SOBJS))