manifest: Update TF-M with startup files refactoring

Update TF-M revision which reapplies a previous commit
which got reverted during the last upmerge.

Ref: NCSDK-35302

Signed-off-by: Georgios Vasilakis <[email protected]>

Author: Vge0rge

west.yml

@@ -147,7 +147,7 @@ manifest:
     - name: trusted-firmware-m
       repo-path: sdk-trusted-firmware-m
       path: modules/tee/tf-m/trusted-firmware-m
-      revision: df48857af53909c91e02d75d84e46ce3a37f10b4
+      revision: f6e14a12bca533c396c48bbb72b550bad216df2d
     - name: psa-arch-tests
       repo-path: sdk-psa-arch-tests
       path: modules/tee/tf-m/psa-arch-tests