render/vulkan: remove hardcoded validation layers

Users should use the VK_INSTANCE_LAYERS env var to set layers at runtime

render/vulkan/renderer.c

@@ -1938,6 +1938,8 @@ error:
 struct wlr_renderer *wlr_vk_renderer_create_with_drm_fd(int drm_fd) {
 	wlr_log(WLR_INFO, "The vulkan renderer is only experimental and "
 		"not expected to be ready for daily use");
+	wlr_log(WLR_INFO, "Run with VK_INSTANCE_LAYERS=VK_LAYER_KHRONOS_validation "
+		"to enable the validation layer");
 
 	// NOTE: we could add functionality to allow the compositor passing its
 	// name and version to this function. Just use dummies until then,

render/vulkan/vulkan.c

@@ -138,21 +138,13 @@ struct wlr_vk_instance *vulkan_instance_create(bool debug) {
 		.apiVersion = VK_API_VERSION_1_1,
 	};
 
-	const char *layers[] = {
-		"VK_LAYER_KHRONOS_validation",
-		// "VK_LAYER_RENDERDOC_Capture",
-		// "VK_LAYER_live_introspection",
-	};
-
-	unsigned layer_count = debug * (sizeof(layers) / sizeof(layers[0]));
-
 	VkInstanceCreateInfo instance_info = {
 		.sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO,
 		.pApplicationInfo = &application_info,
 		.enabledExtensionCount = extensions_len,
 		.ppEnabledExtensionNames = extensions,
-		.enabledLayerCount = layer_count,
+		.enabledLayerCount = 0,
-		.ppEnabledLayerNames = layers,
+		.ppEnabledLayerNames = NULL,
 	};
 
 	VkDebugUtilsMessageSeverityFlagsEXT severity =