Motor: use default frequency when platform frequency request is predefined value, 0

Motor: use default frequency when platform frequency request is predefined value, 0

Change the default value of frequency from 1 to 0 as following:
- 0 (Use default frequency)
- 1 ~ 8191 (0.1 ~ 819.1 Hz)

And check whether intensity_level is valid or in the early ztm620_motor_run()
function. The intensity_level should be less than count_strength and
count_frequency. The number of count_strength and count_frequency are fixed
according to the h/w device. Each h/w device specifies the number of
count_strength and count_frequency in their own devicetree.

Change-Id: Ie3fd07fbbbf41f72726149864cc0dbe2ac9c71d3
Signed-off-by: jeongsup.jeong <jeongsup.jeong@samsung.com>
[cw00.choi: Add commig-msg as the public style]
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>