[exanic] Power up optical PHYs (if present)

Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/net/exanic.c

 	/* Read capabilities */
 	exanic->caps = readl ( exanic->regs + EXANIC_CAPS );
 
+	/* Power up PHYs */
+	writel ( EXANIC_POWER_ON, ( exanic->regs + EXANIC_POWER ) );
+
 	/* Fetch base MAC address */
 	if ( ( rc = exanic_fetch_mac ( exanic ) ) != 0 )
 		goto err_fetch_mac;

src/drivers/net/exanic.h

 /** I2C GPIO register */
 #define EXANIC_I2C 0x012c
 
+/** Power control register */
+#define EXANIC_POWER 0x0138
+#define EXANIC_POWER_ON 0x000000f0UL		/**< Power on PHYs */
+
 /** Port register offset */
 #define EXANIC_PORT_REGS( index ) ( 0x0200 + ( 0x40 * (index) ) )