Partial MFP4 of 222836:

Only look for FDT partions if our potential parent is a DISK device.

Excluding direct recursion on the flashmap geoms was insufficent because
it did not prevent the underlying device from being retrieved if
flashmap geoms were further partioned.

diff -ruN freebsd/src/sys/geom/geom_flashmap.c beribsd/src/sys/geom/geom_flashmap.c
--- freebsd/src/sys/geom/geom_flashmap.c	2012-11-11 22:16:15.000000000 +0000
+++ beribsd/src/sys/geom/geom_flashmap.c	2013-03-13 20:34:58.000000000 +0000
@@ -174,7 +174,7 @@
 	g_topology_assert();
 
 	if (flags == G_TF_NORMAL &&
-	    !strcmp(pp->geom->class->name, FLASHMAP_CLASS_NAME))
+	    strcmp(pp->geom->class->name, "DISK") != 0)
 		return (NULL);
 
 	gp = g_slice_new(mp, FLASH_SLICES_MAX_NUM, pp, &cp, NULL, 0,