mesa: avoid warning on Windows

On Windows, p_atomic_inc_return returns an unsigned long long rather
than the type the pointer refers to, so let's make sure we cast the
result to the right type. Otherwise, we'll trigger a warning about
the wrong format-string for the type.

Signed-off-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Acked-by: Eric Engestrom <eric@engestrom.ch>
diff --git a/src/gallium/auxiliary/util/u_helpers.c b/src/gallium/auxiliary/util/u_helpers.c
index f28685f..c9da90c 100644
--- a/src/gallium/auxiliary/util/u_helpers.c
+++ b/src/gallium/auxiliary/util/u_helpers.c
@@ -233,7 +233,7 @@
            "    hs_invocations = %"PRIu64"\n"
            "    ds_invocations = %"PRIu64"\n"
            "    cs_invocations = %"PRIu64"\n",
-           p_atomic_inc_return(&counter),
+           (unsigned)p_atomic_inc_return(&counter),
            stats.ia_vertices,
            stats.ia_primitives,
            stats.vs_invocations,