ppc: Remove -fno-strict-aliasing

-fno-strict-aliasing is hidding warnings.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/cpu/74xx_7xx/config.mk b/cpu/74xx_7xx/config.mk
index 324f62b..d589210 100644
--- a/cpu/74xx_7xx/config.mk
+++ b/cpu/74xx_7xx/config.mk
@@ -21,6 +21,6 @@
 # MA 02111-1307 USA
 #
 
-PLATFORM_RELFLAGS += -fPIC -ffixed-r14 -meabi -fno-strict-aliasing
+PLATFORM_RELFLAGS += -fPIC -ffixed-r14 -meabi
 
 PLATFORM_CPPFLAGS += -DCONFIG_74xx_7xx -ffixed-r2 -mstring