Add FWU header files from Trusted Firmware-M

Copy FWU header files interface/include/psa/update.h and
interface/include/tfm_fwu_defs.h from
https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git
commit cea3a2329c855ffcf6b4860ed77ab1e11f5ac5cc

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: I2b8b87205c1fc806652a93146e3b4388c3dc1aa2
2 files changed