pwm: berlin: Put per-channel config into driver data

Instead of allocating extra data in .request() provide the needed memory
in struct berlin_pwm_chip. This reduces the number of allocations. A
side effect is that on suspend and resume the state for all four
channels is always saved and restored. This is easier (and probably
quicker) than looking up the matching pwm_device and checking its
PWMF_REQUESTED bit.

Link: https://lore.kernel.org/r/20230705080650.2353391-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>