layers: Move CmdCopyImage validation into CV

Moved from image layer into buffer module.

Change-Id: If4a826cd8ce311a30d2ce15a820459dbe4b96743
diff --git a/layers/buffer_validation.h b/layers/buffer_validation.h
index 25865e6..849ee49 100644
--- a/layers/buffer_validation.h
+++ b/layers/buffer_validation.h
@@ -121,4 +121,7 @@
 void TransitionFinalSubpassLayouts(core_validation::layer_data *dev_data, GLOBAL_CB_NODE *pCB,
                                    const VkRenderPassBeginInfo *pRenderPassBegin, FRAMEBUFFER_STATE *framebuffer_state);
 
+bool PreCallValidateCmdCopyImage(core_validation::layer_data *device_data, GLOBAL_CB_NODE *cb_node, IMAGE_STATE *src_image_state,
+                                 IMAGE_STATE *dst_image_state, uint32_t region_count, const VkImageCopy *regions);
+
 #endif  // CORE_VALIDATION_BUFFER_VALIDATION_H_