colibri_imx6: set gpr1 ENET_CLK_SEL

This fixes the issue when PHY auto negotiation never completes.

Fixes: 431cd76dd8("colibri_imx6: migrate to DM_ETH")
Signed-off-by: Igor Opaniuk <igor.opaniuk@toradex.com>
Reviewed-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
diff --git a/board/toradex/colibri_imx6/colibri_imx6.c b/board/toradex/colibri_imx6/colibri_imx6.c
index f04b749..d11401e 100644
--- a/board/toradex/colibri_imx6/colibri_imx6.c
+++ b/board/toradex/colibri_imx6/colibri_imx6.c
@@ -354,12 +354,15 @@
 int setup_fec(void)
 {
 	int ret;
+	struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
 
 	/* provide the PHY clock from the i.MX 6 */
 	ret = enable_fec_anatop_clock(0, ENET_50MHZ);
 	if (ret)
 		return ret;
 
+	setbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_ENET_CLK_SEL_MASK);
+
 	return 0;
 }