pan/mdg: Cleanup mir_rewrite_index_src_single

Use idiomatic iterator.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7206>
diff --git a/src/panfrost/midgard/mir.c b/src/panfrost/midgard/mir.c
index 069b875..9dfba6f 100644
--- a/src/panfrost/midgard/mir.c
+++ b/src/panfrost/midgard/mir.c
@@ -26,7 +26,7 @@
 
 void mir_rewrite_index_src_single(midgard_instruction *ins, unsigned old, unsigned new)
 {
-        for (unsigned i = 0; i < ARRAY_SIZE(ins->src); ++i) {
+        mir_foreach_src(ins, i) {
                 if (ins->src[i] == old)
                         ins->src[i] = new;
         }