[COMMON] pwm: pwm-samsung: Initialize PWM Divider, Prescaler.

[COMMON] pwm: pwm-samsung: Initialize PWM Divider, Prescaler.

The reason for initializing PWM Divider and Prescaler is as follows.

- In the past, init function in clk-exynos-pwm.c initialized
Divider and Prescaler, but no longer uses the clk-exynos-pwm.c file.
Therefore, they must be initialized at the time of kernel probe.

- The current bootloader sets the Divider and Prescaler values to use PWM.
After the bootloader finishes, they must be initizlized in kernel.

Change-Id: I9bd0f8e869209380153582bb28a759892ff06ca2
Signed-off-by: Choi Jaehyoung <jkkkkk.choi@samsung.com>