dm: treewide: Rename dev_get_platdata() to dev_get_plat()

Rename this to be consistent with the change from 'platdata'.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/demo.c b/cmd/demo.c
index 90d3cff..78a55f7 100644
--- a/cmd/demo.c
+++ b/cmd/demo.c
@@ -74,7 +74,7 @@
 		printf("entry %d - instance %08x, ops %08x, plat %08x\n",
 		       i++, (uint)map_to_sysmem(dev),
 		       (uint)map_to_sysmem(dev->driver->ops),
-		       (uint)map_to_sysmem(dev_get_platdata(dev)));
+		       (uint)map_to_sysmem(dev_get_plat(dev)));
 	}
 
 	return cmd_process_error(cmdtp, ret);