dm: ns16550: Support CONFIG_SYS_NS16550_MEM32 with driver model

This option is used by some boards, so support it with driver model. This
is really ugly - we should rewrite this driver once all users are moved to
driver model.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
index 3d376d7..9b044a3 100644
--- a/drivers/serial/ns16550.c
+++ b/drivers/serial/ns16550.c
@@ -65,6 +65,8 @@
 	out_le32(addr, value);
 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
 	out_be32(addr, value);
+#elif defined(CONFIG_SYS_NS16550_MEM32)
+	writel(value, addr);
 #elif defined(CONFIG_SYS_BIG_ENDIAN)
 	writeb(value, addr + (1 << shift) - 1);
 #else
@@ -80,6 +82,8 @@
 	return in_le32(addr);
 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
 	return in_be32(addr);
+#elif defined(CONFIG_SYS_NS16550_MEM32)
+	return readl(addr);
 #elif defined(CONFIG_SYS_BIG_ENDIAN)
 	return readb(addr + (1 << shift) - 1);
 #else