nvs_flash: build nvs_encr.cpp only if relevant config option is enabled

components/nvs_flash/CMakeLists.txt

@@ -1,10 +1,14 @@
-idf_component_register(SRCS "src/nvs_api.cpp"
-                            "src/nvs_encr.cpp"
+set(srcs "src/nvs_api.cpp"
          "src/nvs_item_hash_list.cpp"
          "src/nvs_ops.cpp"
          "src/nvs_page.cpp"
          "src/nvs_pagemanager.cpp"
          "src/nvs_storage.cpp"
-                            "src/nvs_types.cpp"
+         "src/nvs_types.cpp")
+if(CONFIG_NVS_ENCRYPTION)
+    list(APPEND srcs "src/nvs_encr.cpp")
+endif()
+
+idf_component_register(SRCS "${srcs}"
                     REQUIRES spi_flash mbedtls
                     INCLUDE_DIRS include)

components/nvs_flash/component.mk

@@ -5,3 +5,7 @@
 COMPONENT_ADD_INCLUDEDIRS := include
 
 COMPONENT_SRCDIRS := src
+
+ifndef CONFIG_NVS_ENCRYPTION
+COMPONENT_OBJEXCLUDE := src/nvs_encr.o
+endif