Remove shell variable UNDEF_SYM.

UNDEF_SYM is a shell variable in the main Makefile used to force the
linker to add all u-boot commands to the final image. It has no use here.

Signed-off-by: Kenneth Johansson <kenneth@southpole.se>
diff --git a/nand_spl/board/amcc/sequoia/Makefile b/nand_spl/board/amcc/sequoia/Makefile
index 93150aa..fba0322 100644
--- a/nand_spl/board/amcc/sequoia/Makefile
+++ b/nand_spl/board/amcc/sequoia/Makefile
@@ -50,7 +50,7 @@
 	$(OBJCOPY) ${OBJCFLAGS} -O binary $< $@
 
 $(nandobj)u-boot-spl:	$(OBJS)
-	cd $(LNDIR) && $(LD) $(LDFLAGS) $$UNDEF_SYM $(__OBJS) \
+	cd $(LNDIR) && $(LD) $(LDFLAGS) $(__OBJS) \
 		-Map $(nandobj)u-boot-spl.map \
 		-o $(nandobj)u-boot-spl