pwm: modify PWM_LOOKUP to initialize all struct pwm_lookup members

Now that PWM_LOOKUP is not used anymore, modify it to initialize all the
members of struct pwm_lookup.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

diff --cc Documentation/pwm.txt
Simple merge

diff --cc include/linux/pwm.h
Simple merge