Move cont_init from ram to flash

Author: kylefleming

cores/esp8266/cont_util.c

@@ -25,7 +25,7 @@
 
 #define CONT_STACKGUARD 0xfeefeffe
 
-void ICACHE_RAM_ATTR cont_init(cont_t* cont) {
+void cont_init(cont_t* cont) {
     cont->stack_guard1 = CONT_STACKGUARD;
     cont->stack_guard2 = CONT_STACKGUARD;
     cont->stack_end = cont->stack + (sizeof(cont->stack) / 4);