timer: start a new timer after relocation

Start a new timer after relocation, just in case the
timer has been used in per-relocation.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/common/board_r.c b/common/board_r.c
index f8c1baa..a4facf8 100644
--- a/common/board_r.c
+++ b/common/board_r.c
@@ -290,6 +290,9 @@
 	/* Save the pre-reloc driver model and start a new one */
 	gd->dm_root_f = gd->dm_root;
 	gd->dm_root = NULL;
+#ifdef CONFIG_TIMER
+	gd->timer = NULL;
+#endif
 	return dm_init_and_scan(false);
 }
 #endif