snowball: Set TARGET_EXTRA_CFLAGS

Use CPU specific optimizations if available

Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>
diff --git a/BoardConfig.mk b/BoardConfig.mk
index d753f62..563196b 100644
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -41,3 +41,6 @@
 #TARGET_USERIMAGES_SPARSE_EXT_DISABLED := true
 
 #TARGET_USE_GATOR:= true
+
+# Snowball uses a Nova A9500 -- Dual-Core Cortex A9
+TARGET_EXTRA_CFLAGS += $(call cc-option,-mtune=cortex-a9,$(call cc-option,-mtune=cortex-a8)) $(call cc-option,-mcpu=cortex-a9,$(call cc-option,-mcpu=cortex-a8))