mmc: sunxi: conditionally include MMC2 initialization code

Allwinner R329 has no MMC2.

Only include the code of MMC2 if the base address of it is defined.

Signed-off-by: Icenowy Zheng <icenowy@sipeed.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/drivers/mmc/sunxi_mmc.c b/drivers/mmc/sunxi_mmc.c
index c170c16..4bf8a9b 100644
--- a/drivers/mmc/sunxi_mmc.c
+++ b/drivers/mmc/sunxi_mmc.c
@@ -72,10 +72,12 @@
 		priv->reg = (struct sunxi_mmc *)SUNXI_MMC1_BASE;
 		priv->mclkreg = &ccm->sd1_clk_cfg;
 		break;
+#ifdef SUNXI_MMC2_BASE
 	case 2:
 		priv->reg = (struct sunxi_mmc *)SUNXI_MMC2_BASE;
 		priv->mclkreg = &ccm->sd2_clk_cfg;
 		break;
+#endif
 #ifdef SUNXI_MMC3_BASE
 	case 3:
 		priv->reg = (struct sunxi_mmc *)SUNXI_MMC3_BASE;