rp: don't use SetConfig trait in PWM and PIO.

It was intended to allow changing baudrate on shared spi/i2c. There's no
advantage in using it for PWM or PIO, and makes it less usable because you have to
have `embassy-embedded-hal` as a dep to use it.

examples/rp/src/bin/pio_hd44780.rs

@@ -4,7 +4,6 @@
 
 use core::fmt::Write;
 
-use embassy_embedded_hal::SetConfig;
 use embassy_executor::Spawner;
 use embassy_rp::dma::{AnyChannel, Channel};
 use embassy_rp::peripherals::PIO0;