v3dv: Destroy the device mutex on the teardown path

Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15704>

src/broadcom/vulkan/v3dv_device.c

@@ -1998,6 +1998,7 @@ v3dv_CreateDevice(VkPhysicalDevice physicalDevice,
 
 fail:
    destroy_device_syncs(device, physical_device->render_fd);
+   mtx_destroy(&device->mutex);
    vk_device_finish(&device->vk);
    vk_free(&device->vk.alloc, device);