pan/bi: Add secondary staging count

Useful for instructions with two independent sets of staging registers
(like dual source blending or dual texturing).

Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13723>

src/panfrost/bifrost/compiler.h

@@ -409,7 +409,10 @@ typedef struct {
                 };
 
                 /* TEXC, ATOM_CX: # of staging registers used */
-                uint32_t sr_count;
+                struct {
+                        uint32_t sr_count;
+                        uint32_t sr_count_2;
+                };
         };
 
         /* Modifiers specific to particular instructions are thrown in a union */