adc: iio: hardware: reduce STM32 ADC sampling rate to 80Hz

And 4x oversampling. The slower sampling rate and oversampling factor is
still sufficient to keep the noise level low and reduces the CPU load a bit.

Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>

Author: hnez

src/adc/iio/hardware.rs

@@ -407,9 +407,9 @@ impl IioThread {
             "stm32",
             "48003000.adc:adc@0",
             "tim4_trgo",
-            1024,
+            80,
             CHANNELS_STM32,
-            128,
+            4,
         )
         .await
     }