Correct relocation fixup for mpc5xx

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/cpu/mpc5xx/config.mk b/cpu/mpc5xx/config.mk
index 64cd600..e95b8a1 100644
--- a/cpu/mpc5xx/config.mk
+++ b/cpu/mpc5xx/config.mk
@@ -28,7 +28,7 @@
 #
 
 
-PLATFORM_RELFLAGS += 	-fPIC -ffixed-r14 -meabi
+PLATFORM_RELFLAGS += 	-fPIC -ffixed-r14 -meabi -mrelocatable
 
 PLATFORM_CPPFLAGS +=	-DCONFIG_5xx -ffixed-r2 -ffixed-r29 -mpowerpc -msoft-float