PM / devfreq: Fix handling dev_pm_qos_remove_request result

The dev_pm_qos_remove_request function can return 1 if
"aggregated constraint value has changed" so only negative values should
be reported as errors.

Fixes: 27dbc542 ("PM / devfreq: Use PM QoS for sysfs min/max_freq")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>