Added missing implementation of 'platform_pwrButtonStatus' in linux platform.c

platform/targets/linux/platform.c

@@ -73,6 +73,11 @@ bool platform_getPttStatus()
     return Radio_State.PttStatus;
 }
 
+bool platform_pwrButtonStatus()
+{
+    /* Suppose radio is always on */
+    return true;
+}
 
 void platform_ledOn(__attribute__((unused)) led_t led)
 {