ci: add `-UFASTPATH` to build_all

To catch issue in from `spa_log_trace_fp()` and
`pw_log_trace_fp()` macro invocations.

.gitlab-ci.yml

@@ -305,6 +305,8 @@ build_all:
         -Droc=disabled
         -Dlibcamera=disabled
         -Dsession-managers=[]
+        -Dc_args="['-UFASTPATH']"
+        -Dcpp_args="['-UFASTPATH']"
   parallel:
     matrix:
       - CC: [gcc, clang]