i2c: designware: retry transfer on transient failure

Set the i2c_adapter retries field to a sensible value. This allows the i2c core
to retry master_xfer() when it returns -EAGAIN. Currently the i2c-designware
driver returns -EAGAIN only on Tx arbitration failure (DW_IC_TX_ARB_LOST).

Reported-by: Rolland Chau <zourongrong@gmail.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-designware-core.c

@@ -854,6 +854,7 @@ int i2c_dw_probe(struct dw_i2c_dev *dev)
 
 	snprintf(adap->name, sizeof(adap->name),
 		 "Synopsys DesignWare I2C adapter");
+	adap->retries = 3;
 	adap->algo = &i2c_dw_algo;
 	adap->dev.parent = dev->dev;
 	i2c_set_adapdata(adap, dev);