bootstd: Set the distro_bootpart env var with scripts

This environment variable is supposed to be set so that the script knows
which partition holds the script. Set it before invoking the script.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/boot/bootmeth_script.c b/boot/bootmeth_script.c
index 3a3907d..7050e45 100644
--- a/boot/bootmeth_script.c
+++ b/boot/bootmeth_script.c
@@ -126,6 +126,8 @@
 	if (!ret)
 		ret = env_set_hex("devnum", desc->devnum);
 	if (!ret)
+		ret = env_set_hex("distro_bootpart", bflow->part);
+	if (!ret)
 		ret = env_set("prefix", bflow->subdir);
 	if (!ret && IS_ENABLED(CONFIG_ARCH_SUNXI) &&
 	    !strcmp("mmc", blk_get_devtype(bflow->blk)))
@@ -135,6 +137,7 @@
 
 	log_debug("devtype: %s\n", env_get("devtype"));
 	log_debug("devnum: %s\n", env_get("devnum"));
+	log_debug("distro_bootpart: %s\n", env_get("distro_bootpart"));
 	log_debug("prefix: %s\n", env_get("prefix"));
 	log_debug("mmc_bootdev: %s\n", env_get("mmc_bootdev"));
 
diff --git a/include/bootflow.h b/include/bootflow.h
index bf71b09..ed9b61f 100644
--- a/include/bootflow.h
+++ b/include/bootflow.h
@@ -144,6 +144,8 @@
  *	appear first, then the global ones, if any
  * @doing_global: true if we are iterating through the global bootmeths (which
  *	happens before the normal ones)
+ * @method_flags: flags controlling which methods should be used for this @dev
+ * (enum bootflow_meth_flags_t)
  */
 struct bootflow_iter {
 	int flags;
@@ -161,6 +163,7 @@
 	int first_glob_method;
 	struct udevice **method_order;
 	bool doing_global;
+	int method_flags;
 };
 
 /**