recovery: Disable kernel_afdo on recovery image.

kernel afdo was enabled on recovery images but it pushed the
image to > 8MB on daisy boards resulting in failure at Archive stage.
Since there is no need that recovery image kernel for afdo, just disable it.

BUG=chromium:772450
TEST=Recovery image size is < 8MB on daisy.

Change-Id: I8e12279ccfc53a4598cbd45710abd5c0db014f50
Reviewed-on: https://chromium-review.googlesource.com/716922
Commit-Queue: Manoj Gupta <manojgupta@chromium.org>
Tested-by: Manoj Gupta <manojgupta@chromium.org>
Trybot-Ready: Manoj Gupta <manojgupta@chromium.org>
Reviewed-by: Ting-Yuan Huang <laszio@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/mod_image_for_recovery.sh b/mod_image_for_recovery.sh
index ba92883..7d94846 100755
--- a/mod_image_for_recovery.sh
+++ b/mod_image_for_recovery.sh
@@ -400,7 +400,7 @@
 
 # Build the recovery kernel.
 FACTORY_ROOT="${BOARD_ROOT}/factory-root"
-RECOVERY_KERNEL_FLAGS="fbconsole vtconsole recovery_ramfs tpm i2cdev vfat"
+RECOVERY_KERNEL_FLAGS="fbconsole vtconsole recovery_ramfs tpm i2cdev vfat -kernel_afdo"
 USE="${RECOVERY_KERNEL_FLAGS}" emerge_custom_kernel "$FACTORY_ROOT" ||
   failboat "Cannot emerge custom kernel"