Enable slow boot user notification

Enable slow boot user notification under firmware update scenario.

BUG=b:129056373
TEST=Boot to ChromeOS. Ensure that the slow boot user notification is
enabled and displayed when there is an auto-update involving a firmware
update.

Cq-Depend: chromium:1831334, chromium:1768809
Change-Id: Iecda148e757da4401ca8a8b4ac870d0ee5620853
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/board-overlays/+/1831336
Commit-Queue: Karthikeyan Ramasubramanian <kramasub@chromium.org>
Tested-by: Karthikeyan Ramasubramanian <kramasub@chromium.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
diff --git a/overlay-octopus/profiles/base/make.defaults b/overlay-octopus/profiles/base/make.defaults
index d966b31..505a916 100644
--- a/overlay-octopus/profiles/base/make.defaults
+++ b/overlay-octopus/profiles/base/make.defaults
@@ -41,3 +41,6 @@
 
 # Enable CPU zero-copy for Chrome camera stack.
 USE="${USE} video_capture_use_gpu_memory_buffer"
+
+# Enable slow boot notification
+USE="${USE} enable_slow_boot_notify"