examples: enable gc-sections option

This fixes building time.c when unreferenced functions are added.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>

examples/api/Makefile

@@ -53,7 +53,7 @@ all:	$(obj).depend $(OUTPUT)
 #########################################################################
 
 $(OUTPUT):	$(OBJS)
-		$(LD) -Ttext $(LOAD_ADDR) -o $@ $^ $(PLATFORM_LIBS)
+		$(LD) --gc-sections -Ttext $(LOAD_ADDR) -o $@ $^ $(PLATFORM_LIBS)
 		$(OBJCOPY) -O binary $@ $(OUTPUT).bin 2>/dev/null
 
 # Rule to build generic library C files