common: Move autoprobe out to board init

Rather than doing autoprobe within the driver model code, move it out to
the board-init code. This makes it clear that it is a separate step from
binding devices.

For now this is always done twice, before and after relocation, but we
should discuss whether it might be possible to drop the post-relocation
probe.

For boards with SPL, the autoprobe is still done there as well.

Note that with this change, autoprobe happens after the
EVT_DM_POST_INIT_R/F events are sent, rather than before.

Link: https://lore.kernel.org/u-boot/20240626235717.272219-1-marex@denx.de/

Signed-off-by: Simon Glass <sjg@chromium.org>

include/dm/root.h

@@ -136,6 +136,21 @@ int dm_scan_other(bool pre_reloc_only);
  */
 int dm_init_and_scan(bool pre_reloc_only);
 
+/**
+ * dm_autoprobe() - Probe devices which are marked for probe-after-bind
+ *
+ * This probes all devices with a DM_FLAG_PROBE_AFTER_BIND flag. It checks the
+ * entire tree, so parent nodes need not have the flag set.
+ *
+ * It recursively probes parent nodes, so they do not need to have the flag
+ * set themselves. Since parents are always probed before children, if a child
+ * has the flag set, then its parent (and any devices up the chain to the root
+ * device) will be probed too.
+ *
+ * Return: 0 if OK, -ve on error
+ */
+int dm_autoprobe(void);
+
 /**
  * dm_init() - Initialise Driver Model structures
  *