rptun: add CONFIG_RPTUN_LOADER to optimize code size

Change-Id: I8a8d85eba5058d455d4ca8a8627169cf29060a4d
Signed-off-by: Jiuzhu Dong <dongjiuzhu1@xiaomi.com>

drivers/rptun/Kconfig

@@ -20,4 +20,8 @@ config RPTUN_STACKSIZE
 	int "rptun stack size"
 	default DEFAULT_TASK_STACKSIZE
 
+config RPTUN_LOADER
+        bool "rptun loader support"
+        default n
+
 endif # RPTUN

drivers/rptun/rptun.c

@@ -389,6 +389,7 @@ static int rptun_dev_start(FAR struct remoteproc *rproc)
       return ret;
     }
 
+#ifdef CONFIG_RPTUN_LOADER
   if (RPTUN_GET_FIRMWARE(priv->dev))
     {
       struct rptun_store_s store =
@@ -406,6 +407,7 @@ static int rptun_dev_start(FAR struct remoteproc *rproc)
       rsc = rproc->rsc_table;
     }
   else
+#endif
     {
       rsc = RPTUN_GET_RESOURCE(priv->dev);
       if (!rsc)