pwm: clps711x: Fix period calculation

pwm: clps711x: Fix period calculation

[ Upstream commit b0f17570b8203c22f139459c86cfbaa0311313ed ]

Commit e39c0df1be5a ("pwm: Introduce the pwm_args concept") has
changed the variable for the period for clps711x-pwm driver, so now
pwm_get/set_period() works with pwm->state.period variable instead
of pwm->args.period.
This patch changes the period variable in other places where it is used.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>