ci: Pin tf-m-tests version in FIH test

To avoid problems where the latest master of tf-m-tests is incompatible
with the fixed version used by the FIH test. Bump the version of TF-M
used slightly to a commit that allows the version of tf-m-tests to be
easily overridden.

Signed-off-by: Raef Coles <raef.coles@arm.com>
diff --git a/ci/fih_test_docker/execute_test.sh b/ci/fih_test_docker/execute_test.sh
index dc00f80..7b09ecd 100755
--- a/ci/fih_test_docker/execute_test.sh
+++ b/ci/fih_test_docker/execute_test.sh
@@ -47,6 +47,7 @@
     -DTFM_PSA_API=ON \
     -DMCUBOOT_PATH=$MCUBOOT_PATH \
     -DMCUBOOT_LOG_LEVEL=INFO \
+    -DTFM_TEST_REPO_VERSION=93ce2f59c0c4a9cba6062834496b5f45deee4010 \
     $CMAKE_FIH_LEVEL \
     .
 cd $TFM_BUILD_DIR
@@ -63,4 +64,4 @@
 echo "    - SKIP_SIZE: $SKIP_SIZE"
 echo "    - DAMAGE_TYPE: $DAMAGE_TYPE"
 
-python3 $MCUBOOT_PATH/ci/fih_test_docker/generate_test_report.py fih_test_output.yaml
\ No newline at end of file
+python3 $MCUBOOT_PATH/ci/fih_test_docker/generate_test_report.py fih_test_output.yaml