boot/espressif: Update main.c to call init and loader functions

Add ESP specific loader code to load host application

Signed-off-by: Shubham Kulkarni <shubham.kulkarni@espressif.com>
diff --git a/boot/espressif/include/esp_loader.h b/boot/espressif/include/esp_loader.h
new file mode 100644
index 0000000..e22ce06
--- /dev/null
+++ b/boot/espressif/include/esp_loader.h
@@ -0,0 +1,9 @@
+/*
+ * Copyright (c) 2021 Espressif Systems (Shanghai) Co., Ltd.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#pragma once
+
+void esp_app_image_load(int slot, unsigned int hdr_offset);