thermal: step_wise: Appease the kernel-doc deity

thermal: step_wise: Appease the kernel-doc deity

Replace - with : to appease the kernel-doc gods and fix warnings such as
the following when compiled with make W=1:

linux-amit.git/drivers/thermal/step_wise.c:187: warning: Function
parameter or member 'tz' not described in 'step_wise_throttle'
linux-amit.git/drivers/thermal/step_wise.c:187: warning: Function
parameter or member 'trip' not described in 'step_wise_throttle'

linux.git/drivers/thermal/fair_share.c:79: warning: Function parameter
or member 'tz' not described in 'fair_share_throttle'
linux.git/drivers/thermal/fair_share.c:79: warning: Function parameter
or member 'trip' not described in 'fair_share_throttle'

Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/5d48ac6f85667a53902092ad5bbfef8cc89a7162.1574242756.git.amit.kucheria@linaro.org