pwm: hibvt: Add hi3559v100 support

Add support for the hi3559v100-shub-pwm and hisilicon,hi3559v100-pwm
platforms. They require a special quirk: the PWM has to be enabled twice
to force a duty_cycle refresh.

Signed-off-by: Mathieu Othacehe <m.othacehe@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>