Documentation/getting_started/kconfig.md: Add a note about Kconfig defaults

When the declaration is done after the default, menuconfig will see that
symbol defined at the first place where kconfig tool will find it.
For example, if we run menuconfig and search for 'MAINBOARD_VENDOR', we
will see it defined at ""src/mainboard/51nb/Kconfig" which is odd.

Change-Id: I215a1817e60e6deb6931679f139d110ba762d3c8
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45127
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Nico Huber <nico.h@gmx.de>

0 files changed, 0 insertions, 0 deletions