ppc: remove -ffixed-r14 gcc option.

This is no loger needed, free up r14 for general usage.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
diff --git a/cpu/mpc5xxx/config.mk b/cpu/mpc5xxx/config.mk
index b0ce2ee..5e82f67 100644
--- a/cpu/mpc5xxx/config.mk
+++ b/cpu/mpc5xxx/config.mk
@@ -21,7 +21,7 @@
 # MA 02111-1307 USA
 #
 
-PLATFORM_RELFLAGS += -fPIC -ffixed-r14 -meabi
+PLATFORM_RELFLAGS += -fPIC -meabi
 
 PLATFORM_CPPFLAGS += -DCONFIG_MPC5xxx -ffixed-r2 \
 		     -mstring -mcpu=603e -mmultiple