gallium/util: replace pipe_mutex_unlock() with mtx_unlock()

pipe_mutex_unlock() was made unnecessary with fd33a6bcd7.

Replaced using:
find ./src -type f -exec sed -i -- \
's:pipe_mutex_unlock(\([^)]*\)):mtx_unlock(\&\1):g' {} \;

Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/gallium/drivers/ddebug/dd_draw.c

@@ -942,7 +942,7 @@ PIPE_THREAD_ROUTINE(dd_thread_pipelined_hang_detect, input)
       }
 
       /* Unlock and sleep before starting all over again. */
-      pipe_mutex_unlock(dctx->mutex);
+      mtx_unlock(&dctx->mutex);
       os_time_sleep(10000); /* 10 ms */
       mtx_lock(&dctx->mutex);
    }
@@ -951,7 +951,7 @@ PIPE_THREAD_ROUTINE(dd_thread_pipelined_hang_detect, input)
    while (dctx->records)
       dd_free_record(&dctx->records);
 
-   pipe_mutex_unlock(dctx->mutex);
+   mtx_unlock(&dctx->mutex);
    return 0;
 }
 
@@ -1044,7 +1044,7 @@ dd_pipelined_process_draw(struct dd_context *dctx, struct dd_call *call)
    mtx_lock(&dctx->mutex);
    record->next = dctx->records;
    dctx->records = record;
-   pipe_mutex_unlock(dctx->mutex);
+   mtx_unlock(&dctx->mutex);
 }
 
 static void