board: sunxi: change trace level for phy errors managed by uclass

As the error message is now displayed by generic phy functions,
the pr_err can be change to pr_idebug.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/board/sunxi/board.c b/board/sunxi/board.c
index 71e2b75..a5cf0b6 100644
--- a/board/sunxi/board.c
+++ b/board/sunxi/board.c
@@ -711,7 +711,7 @@
 
 	ret = generic_phy_init(&phy);
 	if (ret) {
-		pr_err("failed to init %s USB PHY\n", dev->name);
+		pr_debug("failed to init %s USB PHY\n", dev->name);
 		return ret;
 	}