i2c: thunderx: Enable HWMON class probing

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

Set I2C_CLASS_HWMON to enable automatic probing of BMC devices
by the ipmi-ssif driver.
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
(cherry picked from commit 889ef45c)
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-thunderx-pcidrv.c

@@ -205,6 +205,7 @@ static int thunder_i2c_probe_pci(struct pci_dev *pdev,
 
 	i2c->adap = thunderx_i2c_ops;
 	i2c->adap.retries = 5;
+	i2c->adap.class = I2C_CLASS_HWMON;
 	i2c->adap.bus_recovery_info = &octeon_i2c_recovery_info;
 	i2c->adap.dev.parent = dev;
 	i2c->adap.dev.of_node = pdev->dev.of_node;