pwm: add pwm driver for s7 [2/2]

PD#SWPL-135717

Problem:
there is no s7 pwm driver

Solution:
add s7 pwm driver

Verify:
s7 pxp

Change-Id: Id2cda8a5c05c7c0961eaa351a45a1ef189eddb42
Signed-off-by: junyi.zhao <junyi.zhao@amlogic.com>
10 files changed