Eclair-builds: Modify git commands to checkout index and clean

Use git checkout-index to checkout the index into the working
tree (forced, for all files, quiet). Expand on using git clean
to remove all files in the working tree which are not in the
index (forced, for all files and directories, quiet). This
should fixed the recent issue with eclair-daily builds due to
the new RPI2350 patch on psa-arch-tests fetch_repo().

Signed-off-by: Antonio de Angelis <antonio.deangelis@arm.com>
Change-Id: I85c325fcaa1363d76c7fccf8a197efa58e1e9dab
diff --git a/run-eclair-builds.sh b/run-eclair-builds.sh
index 202e469..3ed9e7f 100755
--- a/run-eclair-builds.sh
+++ b/run-eclair-builds.sh
@@ -16,9 +16,9 @@
 for cfg in $(python3 ./tf-m-ci-scripts/configs.py -g "$FILTER_GROUP"); do
     echo "============== $cfg ($cnt/$num_configs) =============="
     export CONFIG_NAME=$cfg
-    (cd mbedtls; git checkout .; git clean -fq)
-    (cd psa-arch-tests; git checkout .; git clean -fq)
-    (cd trusted-firmware-m; git checkout .; git clean -fq)
+    (cd mbedtls; git checkout-index -faq; git clean -fdq)
+    (cd psa-arch-tests; git checkout-index -faq; git clean -fdq)
+    (cd trusted-firmware-m; git checkout-index -faq; git clean -fdq)
     eclair_tfm_set_toolchain_path
     detachLicense $LICENSE_LEASE
     tf-m-ci-scripts/run-build.sh