Instead of providing an EC_SIG binary blob, generate it at build time
using the mec152x tool. Allows to move the EC_BODY in the fmap without
the need to generate a new EC_SIG.
TEST=Booted on amd/birman_plus without EC_SIG blob.
Change-Id: I2d7a791820d905b088194b290853509f10689fc6
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/87429
Reviewed-by: Maximilian Brune <maximilian.brune@9elements.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>