Makefile: deprecate config DIAGNOSTIC_UI

DIAGNOSTIC_UI is indirectly decided by the diag_payload and minidiag use
flag from depthcharge.
But with introducing the diagnostic boot mode, coreboot also needs to
build minidiag utility functions and enable this building flag.
Therefore we consider to deprecate DIAGNOSTIC_UI and always build them.

For diag_payload:
It is for a diagnostic tool which based on legacy UI and deprecated

For minidiag:
Mini-diag is set default enabled for newer devices, and we could still
use kernel secdata in runtime if we decide to disable it on certain
platforms.

In conclusion, deprecating DIAGNOSTIC_UI will not affect newer devices.

BUG=b:190796342, b:181931817
BRANCH=none
TEST=emerge-volteer depthcharge
TEST=emerge-volteer coreboot
TEST=CC=x86_64-pc-linux-gnu-clang;
     make clean && make runtests

Cq-Depend: chromium:3004223
Signed-off-by: Hsuan Ting Chen <roccochen@chromium.org>
Change-Id: I0d804bcd9d31d3952c744a1926ac59cde7b7f841
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/3006114
Reviewed-by: Yu-Ping Wu <yupingso@chromium.org>
5 files changed