i2c: octeon: thunderx: TWSI software reset in recovery

BugLink: https://bugs.launchpad.net/bugs/1688132

I've seen i2c recovery reporting long loops of:

[ 1035.887818] i2c i2c-4: SCL is stuck low, exit recovery
[ 1037.999748] i2c i2c-4: SCL is stuck low, exit recovery
[ 1040.111694] i2c i2c-4: SCL is stuck low, exit recovery
...

Add a TWSI software reset which clears the status and
STA,STP,IFLG in SW_TWSI_EOP_TWSI_CTL.

With this the recovery works fine and above message is not seen.
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
(cherry picked from commit ccee1a4c)
Signed-off-by: dann frazier <dann.frazier@canonical.com>
Acked-by: Colin King <colin.king@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

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

@@ -789,6 +789,9 @@ static void octeon_i2c_prepare_recovery(struct i2c_adapter *adap)
 	struct octeon_i2c *i2c = i2c_get_adapdata(adap);
 
 	octeon_i2c_hlc_disable(i2c);
+	octeon_i2c_reg_write(i2c, SW_TWSI_EOP_TWSI_RST, 0);
+	/* wait for software reset to settle */
+	udelay(5);
 
 	/*
 	 * Bring control register to a good state regardless