pwm: Let pwm_set_waveform_might_sleep() fail for exact but impossible requests

pwm: Let pwm_set_waveform_might_sleep() fail for exact but impossible requests

Up to now pwm_set_waveform_might_sleep() returned 1 for exact requests
that couldn't be served exactly. In contrast to
pwm_round_waveform_might_sleep() and pwm_set_waveform_might_sleep() with
exact = false this is an error condition. So simplify handling for
callers of pwm_set_waveform_might_sleep() by returning -EDOM instead of
1 in this case.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20538a46719584dafd8a1395c886780a97dcdf79.1746010245.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>