ath79: optimize ath79 tiny target for size

the speed impact on tiny target is minimal and worth the size gained

Signed-off-by: Lucian Cristian <[email protected]>

target/linux/ath79/tiny/config-default

@@ -1,3 +1,5 @@
+# CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE is not set
+CONFIG_CC_OPTIMIZE_FOR_SIZE=y
 CONFIG_BLK_MQ_PCI=y
 CONFIG_LEDS_RESET=y
 CONFIG_OF_ADDRESS_PCI=y