ns16550: unify serial_omap

Unify serial_omap, and use the generic binding.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Reviewed-by: Tom Rini <trini@konsulko.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/board/quipos/cairo/cairo.c b/board/quipos/cairo/cairo.c
index b97a09a..21793e8 100644
--- a/board/quipos/cairo/cairo.c
+++ b/board/quipos/cairo/cairo.c
@@ -97,7 +97,7 @@
 };
 
 U_BOOT_DEVICE(cairo_uart) = {
-	"serial_omap",
+	"ns16550_serial",
 	&cairo_serial
 };