sunxi: Fix A20-OLinuXino-MICRO LAN8710 support

>From revision J the board uses new phy chip LAN8710. Compared
with RTL8201, RA17 pin is TXERR. It has pullup which causes phy
not to work. To fix this PA17 is muxed with GMAC function. This
makes the pin output-low.
Signed-off-by: NStefan Mavrodiev <stefan@olimex.com>
Acked-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: NJagan Teki <jagan@openedev.com>

board/sunxi/gmac.c

@@ -33,7 +33,11 @@ void eth_init_board(void)
 
 #ifndef CONFIG_MACH_SUN6I
 	/* Configure pin mux settings for GMAC */
+#ifdef CONFIG_SUN7I_GMAC_FORCE_TXERR
+	for (pin = SUNXI_GPA(0); pin <= SUNXI_GPA(17); pin++) {
+#else
 	for (pin = SUNXI_GPA(0); pin <= SUNXI_GPA(16); pin++) {
+#endif
 #ifdef CONFIG_RGMII
 		/* skip unused pins in RGMII mode */
 		if (pin == SUNXI_GPA(9) || pin == SUNXI_GPA(14))

configs/A20-OLinuXino_MICRO-eMMC_defconfig

@@ -19,6 +19,7 @@ CONFIG_SPL_I2C_SUPPORT=y
 # CONFIG_SPL_EFI_PARTITION is not set
 CONFIG_ETH_DESIGNWARE=y
 CONFIG_SUN7I_GMAC=y
+CONFIG_SUN7I_GMAC_FORCE_TXERR=y
 CONFIG_AXP_ALDO3_VOLT=2800
 CONFIG_AXP_ALDO4_VOLT=2800
 CONFIG_SCSI=y

configs/A20-OLinuXino_MICRO_defconfig

@@ -20,6 +20,7 @@ CONFIG_SPL_I2C_SUPPORT=y
 # CONFIG_SPL_EFI_PARTITION is not set
 CONFIG_ETH_DESIGNWARE=y
 CONFIG_SUN7I_GMAC=y
+CONFIG_SUN7I_GMAC_FORCE_TXERR=y
 CONFIG_AXP_ALDO3_VOLT=2800
 CONFIG_AXP_ALDO4_VOLT=2800
 CONFIG_SCSI=y

drivers/net/Kconfig

@@ -244,6 +244,14 @@ config SUN7I_GMAC
 	help
 	  Enable the support for Sun7i GMAC Ethernet controller
 
+config SUN7I_GMAC_FORCE_TXERR
+	bool "Force PA17 as gmac function"
+	depends on SUN7I_GMAC
+	help
+	  Some ethernet phys needs TXERR control. Since the GMAC
+	  doesn't have such signal, setting PA17 as GMAC function
+	  makes the pin output low, which enables data transmission.
+
 config SUN4I_EMAC
 	bool "Allwinner Sun4i Ethernet MAC support"
 	depends on DM_ETH