rust: pwm: Drop wrapping of PWM polarity and state

rust: pwm: Drop wrapping of PWM polarity and state

These were introduced and used in an earlier revision of the patch that
became commit fb3957af9ec6 ("pwm: Add Rust driver for T-HEAD TH1520
SoC"). The variant that was actually applied sticks to the modern
waveform abstraction only (and other drivers are supposed to do that,
too), so they can be dropped.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://patch.msgid.link/20251025122359.361372-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>