Boot: Remove forked MCUboot from TF-M

Remove the generic MCUboot source files from TF-M in order to
rely only on upstream MCUboot project as a secure second stage
bootloader. At this point all the features from the internal
fork are already upstreamed to the original project so from
feature point of view the switch is seamless. From now on
any new development is going to be directly upstreamed to the
original project.

Some platform and project specific files and scripts are still
kept in the bl2/ext/mcuboot folder to make possible the integration
with TF-M project.

Signed-off-by: Balint Matyi <Balint.Matyi@arm.com>
Signed-off-by: Tamas Ban <Tamas.Ban@arm.com>
Change-Id: I261c11383202d02eecff06c21d5c51d6ec8f27ea
26 files changed