lp8727_charger: Add supported i2c functionality check routine

lp8727 i2c r/w functions are based on SMBUS I2C BLOCK. So the driver needs to
check whether i2c bus supports this functionality or not.

Signed-off-by: Woogyom Kim <milo.kim@ti.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>

drivers/power/lp8727_charger.c

@@ -425,6 +425,9 @@ static int lp8727_probe(struct i2c_client *cl, const struct i2c_device_id *id)
 	struct lp8727_chg *pchg;
 	int ret;
 
+	if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
+		return -EIO;
+
 	pchg = kzalloc(sizeof(*pchg), GFP_KERNEL);
 	if (!pchg)
 		return -ENOMEM;