samples: pwm: adapt to new api argument definition

Change the api argument format following the API
argument definition change in the driver. Some
definitions of CONSTANTs were changed accordingly.

Correct some comment error.

Jira: ZEP-642

Change-Id: I1b34640aa70f1597076e035e2b3b576d8337129a
Signed-off-by: Baohong Liu <baohong.liu@intel.com>
1 file changed