esp8266/boards: Make sure modespnow.o is placed in irom0.

Signed-off-by: Damien George <damien@micropython.org>

ports/esp8266/boards/esp8266_common.ld

@@ -164,6 +164,7 @@ SECTIONS
         *machine_hspi.o(.literal*, .text*)
         *hspi.o(.literal*, .text*)
         *modesp.o(.literal* .text*)
+        *modespnow.o(.literal* .text*)
         *modos.o(.literal* .text*)
         *modlwip.o(.literal* .text*)
         *modsocket.o(.literal* .text*)