mesa: FramebufferParameteri parameter checking

Missing break; causes parameter checking to
never pass GL_FRAMEBUFFER_FLIP_Y_MESA parameters.

Fixes: 318c265 ("mesa: GL_MESA_framebuffer_flip_y extension [v4]")
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

src/mesa/main/fbobject.c

@@ -1503,6 +1503,7 @@ framebuffer_parameteri(struct gl_context *ctx, struct gl_framebuffer *fb,
       if (!ctx->Extensions.MESA_framebuffer_flip_y)
          goto invalid_pname_enum;
       cannot_be_winsys_fbo = true;
+      break;
    default:
       goto invalid_pname_enum;
    }