netstar: fix crc32.c dependancy location

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
diff --git a/board/netstar/Makefile b/board/netstar/Makefile
index 11a952b..91bac38 100644
--- a/board/netstar/Makefile
+++ b/board/netstar/Makefile
@@ -75,7 +75,7 @@
 $(obj)crcit.o:	crcit.c
 	$(HOSTCC) $(HOST_CFLAGS) -o $@ -c $<
 
-$(obj)crc32.o:	$(OBJTREE)/tools/crc32.c
+$(obj)crc32.o:	$(SRCTREE)/lib_generic/crc32.c
 	$(HOSTCC) $(HOST_CFLAGS) -DUSE_HOSTCC -o $@ -c $<
 
 clean: