psa-arch-tests: Use designated initializers.

Armclang 6.21 reports missing-field-initializers warning for missing
designated initializers. This will be fixed in armclang 6.22.
Currently, use designated initializers as workaround.

Change-Id: I5a40849a0d9a9ba27dff3015c0bb8189669cfbdb
Signed-off-by: Summer Qin <summer.qin@arm.com>
4 files changed