Exynos: Add peripherial id for pwm

Exynos: Add peripherial id for pwm

Add peripherial id for pwm inorder to support
generic api to get the clk frequency

Test with command "sf probe 1:0; time sf read 40008000 0 1000".
Try with different numbers of bytes and see that sane values are obtained
Build and boot U-boot with this patch, backlight works properly.

Signed-off-by: Padmavathi Venna <[email protected]>
Signed-off-by: Akshay Saraswat <[email protected]>
Acked-by: Simon Glass <[email protected]>
Signed-off-by: Minkyu Kang <[email protected]>