nouveau/push: Fix SET_OBJECT handling

My first attempt to fix it ended up stomping classes to zero because it
happened too eary.  Now it happens after we have the whole method parsed
but before we go searching for strings.

Fixes: 8e93a763a3 ("nouveau/push: Handle more recent versions of 6F")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37180>

src/nouveau/headers/nv_push.c

@@ -109,13 +109,6 @@ vk_push_print(FILE *fp, const struct nv_push *push,
          fprintf(fp, "HDR %x subch %i", hdr, subchan);
       }
 
-      if (mthd == 0) { /* SET_OBJECT */
-         curr_subchans[subchan] = value & 0xffff;
-      }
-      int class_id = curr_subchans[subchan];
-      int cls_hi = (class_id & 0xff00) >> 8;
-      int cls_lo = class_id & 0xff;
-
       cur++;
 
       const char *mthd_name = "";
@@ -174,6 +167,16 @@ vk_push_print(FILE *fp, const struct nv_push *push,
       }
 
       while (count--) {
+         if (!is_immd)
+            value = *cur;
+
+         if (mthd == 0) { /* SET_OBJECT */
+            curr_subchans[subchan] = value & 0xffff;
+         }
+         int class_id = curr_subchans[subchan];
+         int cls_hi = (class_id & 0xff00) >> 8;
+         int cls_lo = class_id & 0xff;
+
          if (!is_tert) {
             if (mthd < 0x100) {
                if (cls_hi >= 0xc5)
@@ -250,9 +253,6 @@ vk_push_print(FILE *fp, const struct nv_push *push,
             }
          }
 
-         if (!is_immd)
-            value = *cur;
-
          fprintf(fp, "\tmthd %04x %s\n", mthd, mthd_name);
          if (mthd < 0x100) {
             if (cls_hi >= 0xb0)