Due to different signature keys, the PG1 and the PG2 boards can no
longer use the same FSBL (tiboot3). This makes it impossible anyway to
maintaine a single flash.bin for both variants, so we can also split the
build.
A new target is added to indicates the build is for PG1 vs. PG2 boards.
Hence now the variants have separated defconfig files.
The runtime board_is_sr1() check does make no sense anymore, so remove
it and replace with build time check.
Documentation is updated accordingly. New binary artifacts are already
available via meta-iot2050.
Signed-off-by: Su Baocheng <baocheng.su@siemens.com>
[Jan: refactor config option into targets, tweak some wordings]
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
ea0f45d187