nv30: falling back to draw path for edgeflag does no good

The problem is that the EDGEFLAG has to be toggled at vertex submission
time. This can be done from either the draw or the regular paths. Avoid
falling back to draw just because there's an edgeflag.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Cc: "10.5 10.6" <mesa-stable@lists.freedesktop.org>

src/gallium/drivers/nouveau/nv30/nvfx_vertprog.c

@@ -872,9 +872,8 @@ nvfx_vertprog_parse_decl_output(struct nvfx_vpc *vpc,
       }
       break;
    case TGSI_SEMANTIC_EDGEFLAG:
-      /* not really an error just a fallback */
-      NOUVEAU_ERR("cannot handle edgeflag output\n");
-      return FALSE;
+      vpc->r_result[idx] = nvfx_reg(NVFXSR_NONE, 0);
+      return TRUE;
    default:
       NOUVEAU_ERR("bad output semantic\n");
       return FALSE;