M28: Support for the old M28 SoM v1.0

This prototype version SoM is unused and not available to public.
Support this only for internal debugging purposes.

Signed-off-by: Marek Vasut <marex@denx.de>
diff --git a/board/denx/m28evk/spl_boot.c b/board/denx/m28evk/spl_boot.c
index 91316a7..a04fe18 100644
--- a/board/denx/m28evk/spl_boot.c
+++ b/board/denx/m28evk/spl_boot.c
@@ -72,8 +72,13 @@
 	MX28_PAD_LCD_ENABLE__LCD_ENABLE | MUX_CONFIG_LCD,
 
 	/* UART1 */
+#ifdef	CONFIG_DENX_M28_V10
+	MX28_PAD_AUART0_CTS__DUART_RX,
+	MX28_PAD_AUART0_RTS__DUART_TX,
+#else
 	MX28_PAD_PWM0__DUART_RX,
 	MX28_PAD_PWM1__DUART_TX,
+#endif
 	MX28_PAD_AUART0_TX__DUART_RTS,
 	MX28_PAD_AUART0_RX__DUART_CTS,