pan/bi: Add texture indices to IR

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4844>
diff --git a/src/panfrost/bifrost/compiler.h b/src/panfrost/bifrost/compiler.h
index 9776164..f33595d 100644
--- a/src/panfrost/bifrost/compiler.h
+++ b/src/panfrost/bifrost/compiler.h
@@ -219,6 +219,12 @@
         bool rshift; /* false for lshift */
 };
 
+struct bi_texture {
+        /* Constant indices. Indirect would need to be in src[..] like normal,
+         * we can reserve some sentinels there for that for future. */
+        unsigned texture_index, sampler_index;
+};
+
 typedef struct {
         struct list_head link; /* Must be first */
         enum bi_class type;
@@ -297,6 +303,7 @@
                 unsigned blend_location;
 
                 struct bi_bitwise bitwise;
+                struct bi_texture texture;
         };
 } bi_instruction;