Figure out if CircuitPython on RP2040 can set pullup on ADC

[JohnAZoidberg]

Currently I'm hardcoding it in the firmware.

In the submodule ports/raspberrypi/sdk:

--- a/src/rp2_common/hardware_adc/include/hardware/adc.h
+++ b/src/rp2_common/hardware_adc/include/hardware/adc.h
@@ -71,7 +71,8 @@ static inline void adc_gpio_init(uint gpio) {
     // Select NULL function to make output driver hi-Z
     gpio_set_function(gpio, GPIO_FUNC_NULL);
     // Also disable digital pulls and digital receiver
-    gpio_disable_pulls(gpio);
+    // gpio_disable_pulls(gpio);
+    gpio_pull_up(gpio);
     gpio_set_input_enabled(gpio, false);
 }