hw/net/xilinx_axienet: Auto-clear PHY Autoneg

Auto-clear PHY CR Autoneg bits. This makes this model
work with recent Linux kernels.

Reviewed-by: Francisco Iglesias <frasse.iglesias@gmail.com>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-Id: <20200506082513.18751-2-edgar.iglesias@gmail.com>

hw/net/xilinx_axienet.c

@@ -149,8 +149,8 @@ tdk_write(struct PHY *phy, unsigned int req, unsigned int data)
             break;
     }
 
-    /* Unconditionally clear regs[BMCR][BMCR_RESET] */
-    phy->regs[0] &= ~0x8000;
+    /* Unconditionally clear regs[BMCR][BMCR_RESET] and auto-neg */
+    phy->regs[0] &= ~0x8200;
 }
 
 static void