drivers: thermal: Return zero on success for qmi_tmd_send_state_request

The qmi APIs return a positive transaction result value on successful
qmi message update for all qmi cooling devices. The qmi cooling
devices return the same value for cooling device state update request
from thermal framework. But thermal framework expects zero as return
value for successful cdev update and then only it will update cooling
device stats for that cooling device.

Update qmi cooling device driver to return zero on successful cooling
device state update to thermal framework.

Change-Id: Id9d59ed2c88c7e95dc2746a061e0ebadf0477a30
Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>