SPEAr: Enable autoneg for ethernet

Enabling autoneg avoids situation on few phys with fixed configuration. For
example, in one situation, nfs boot timed out when phy configuration is 100Mbps.
In another situtation, when traffic is directed to SPEAr, either thru
cross-cable or thru switch, the TFTP or DHCP command in u-boot starts to timeout
very often.

When Autoneg is ON, same phys started working perfectly.
Reported-by: NDeepak Sikri <deepak.sikri@st.com>
Reported-by: NArmando Visconti <armando.visconti@st.com>
Signed-off-by: NShiraz Hashim <shiraz.hashim@st.com>
Signed-off-by: NAmit Virdi <amit.virdi@st.com>
Signed-off-by: NStefan Roese <sr@denx.de>

include/configs/spear-common.h

@@ -37,6 +37,7 @@
 #define CONFIG_DW0_PHY				1
 #define CONFIG_NET_MULTI
 #define CONFIG_PHY_RESET_DELAY			10000		/* in usec */
+#define CONFIG_DW_AUTONEG
 
 /* USBD driver configuration */
 #if defined(CONFIG_SPEAR_USBTTY)