Some toolchains are compiled so that they pass a --build-id=something
parameter to the linker implicitly.

This causes U-Boot LTO linking to fail with something like:
  ld: section .note.gnu.build-id LMA ... overlaps section .text LMA ...
because U-Boot's link scripts do not currently handle .note.gnu.build-id
section.

Fix this by explicitly disabling build-id.
Signed-off-by: NMarek Behún <marek.behun@nic.cz>
Reviewed-by: NSimon Glass <sjg@chromium.org>