espressif:esp32: Add multi image support

Changes on configuration and flash area organization for supporting
multi image and implementation for booting on different processors
on esp32

Signed-off-by: Almir Okato <almir.okato@espressif.com>
diff --git a/boot/espressif/include/esp_loader.h b/boot/espressif/include/esp_loader.h
index e22ce06..dc55373 100644
--- a/boot/espressif/include/esp_loader.h
+++ b/boot/espressif/include/esp_loader.h
@@ -6,4 +6,4 @@
 
 #pragma once
 
-void esp_app_image_load(int slot, unsigned int hdr_offset);
+void esp_app_image_load(int image_index, int slot, unsigned int hdr_offset, unsigned int *entry_addr);