mfd: htc-i2cpld: Add the missed i2c_put_adapter() in htcpld_register_chip_i2c()

htcpld_register_chip_i2c() misses to call i2c_put_adapter() in an error
path. Add the missed function call to fix it.

Fixes: 6048a3dd

 ("mfd: Add HTCPLD driver")
Signed-off-by: Jing Xiangfeng <jingxiangfeng@huawei.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>