Add secure storage service

Implements secure storage service client and provider. The client is
compatible with PSA Internal Trusted Storage API. There are two provider
versions implemented:
  * mock_store is a dummy storage for testing purposes,
  * secure_flash_store is a RAM based proof-of-concept storage solution
    based on the ITS implementation in Trusted Firmware-M.

Some files in this commit were forked from Trusted Firmware-M, keeping
the original license header intact:
    tag name: TF-Mv1.1 (8c22a260e24bc5778e5ce0dbdf9da3ccec1da880)
    tagged commit: a6b336c1509fd5f5522450e3cec0fcd6c060f9c8

From 'secure_fw/partitions/internal_trusted_storage/' of TF-M,
   to 'components/service/secure_storage/provider/secure_flash_store/':
       flash/its_flash.c -> flash/sfs_flash.c
       flash/its_flash.h -> flash/sfs_flash.h
       flash/its_flash_info_internal.c -> flash/sfs_flash_info.c
       flash/its_flash_ram.c -> flash/sfs_flash_ram.c
       flash/its_flash_ram.h -> flash/sfs_flash_ram.h
       flash_fs/its_flash_fs.c -> flash_fs/sfs_flash_fs.c
       flash_fs/its_flash_fs.h -> flash_fs/sfs_flash_fs.h
       flash_fs/its_flash_fs_check_info.h ->
                                     flash_fs/sfs_flash_fs_check_info.h
       flash_fs/its_flash_fs_dblock.c -> flash_fs/sfs_flash_fs_dblock.c
       flash_fs/its_flash_fs_dblock.h -> flash_fs/sfs_flash_fs_dblock.h
       flash_fs/its_flash_fs_mblock.c -> flash_fs/sfs_flash_fs_mblock.c
       flash_fs/its_flash_fs_mblock.h -> flash_fs/sfs_flash_fs_mblock.h
       its_utils.c -> sfs_utils.c
       its_utils.h -> sfs_utils.h
       tfm_internal_trusted_storage.c -> secure_flash_store.c
       tfm_internal_trusted_storage.h -> secure_flash_store.h

Change-Id: If9eb3bb7c8a58364a8da9a0b463015b2bbc160c4
Signed-off-by: Balint Dobszay <balint.dobszay@arm.com>
35 files changed