Enable BusyBox timeout command in defconfigs

This change enables the CONFIG_BUSYBOX_CONFIG_TIMEOUT option for
BananaPi-R4, U6Lite, and U6Plus, allowing the use of the BusyBox timeout
utility.

BUG=b:489973420
TEST=upload image to devices and check if timeout cmd
exist
Change-Id: I486407b7fad939fef7bbe88377c0a10455f59b6a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/7637650
Tested-by: Alexandr Astrouski <astrouski@google.com>
Commit-Queue: Alexandr Astrouski <astrouski@google.com>
Reviewed-by: Jason Stanko <jstanko@google.com>