r300-gallium: Point size is at OVM position 15, not 1.

Or so sayeth osiris, and he would know. :3

src/gallium/drivers/r300/r300_state_derived.c

@@ -86,7 +86,7 @@ static void r300_vs_tab_routes(struct r300_context* r300,
                     break;
                 case TGSI_SEMANTIC_PSIZE:
                     psize = TRUE;
-                    tab[i] = 1;
+                    tab[i] = 15;
                     break;
                 case TGSI_SEMANTIC_FOG:
                     fog = TRUE;

src/gallium/drivers/r300/r300_state_tcl.c

@@ -40,6 +40,9 @@ static void r300_vs_declare(struct r300_vs_asm* assembler,
                     /* XXX multiple? */
                     assembler->tab[decl->DeclarationRange.First] = 6;
                     break;
+                case TGSI_SEMANTIC_PSIZE:
+                    assembler->tab[decl->DeclarationRange.First] = 15;
+                    break;
                 default:
                     debug_printf("r300: vs: Bad semantic declaration %d\n",
                         decl->Semantic.SemanticName);