pan/bi: Don't reorder phis in pre-RA scheduling

Treat them like preloads which are also required to be at the start of the
block.

Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17794>

src/panfrost/bifrost/bi_pressure_schedule.c

@@ -204,7 +204,9 @@ create_dag(bi_context *ctx, bi_block *block, void *memctx)
                         add_dep(node, memory_store);
                         memory_load = node;
                         memory_store = node;
-                } else if (I->op == BI_OPCODE_MOV_I32 && I->src[0].type == BI_INDEX_REGISTER) {
+                } else if ((I->op == BI_OPCODE_PHI) ||
+                           (I->op == BI_OPCODE_MOV_I32 &&
+                            I->src[0].type == BI_INDEX_REGISTER)) {
                         preload = node;
                 }
         }