pru: Disable ADC reading directly from the PRU

The PRU code size has grown too close to the maximum - remove the ADC
code to reduce its overall size.  (On the beaglebone, the Linux
process can, and typically does, do the ADC reading.)

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

config/generic-cramps.cfg

@@ -49,7 +49,7 @@ filament_diameter: 1.750
 heater_pin: P9_15
 sensor_type: EPCOS 100K B57560G104F
 pullup_resistor: 2000
-sensor_pin: P9_36
+sensor_pin: host:analog5
 control: pid
 pid_Kp: 22.2
 pid_Ki: 1.08
@@ -61,7 +61,7 @@ max_temp: 250
 heater_pin: P8_11
 sensor_type: EPCOS 100K B57560G104F
 pullup_resistor: 2000
-sensor_pin: P9_33
+sensor_pin: host:analog4
 control: watermark
 min_temp: 0
 max_temp: 130
@@ -73,6 +73,9 @@ pin: P9_41
 serial: /dev/rpmsg_pru30
 pin_map: beaglebone
 
+[mcu host]
+serial: /tmp/klipper_host_mcu
+
 [printer]
 kinematics: cartesian
 max_velocity: 300

docs/beaglebone.md

@@ -71,9 +71,9 @@ make flash
 sudo service klipper start
 ```
 
-For the Replicape, it is also necessary to compile and install the
-micro-controller code for a Linux host process. Run "make menuconfig"
-a second time and configure it for a "Linux process":
+It is also necessary to compile and install the micro-controller code
+for a Linux host process. Run "make menuconfig" a second time and
+configure it for a "Linux process":
 ```
 make menuconfig
 ```

src/pru/Kconfig

@@ -6,7 +6,7 @@ config PRU_SELECT
     bool
     default y
     select HAVE_GPIO
-    select HAVE_GPIO_ADC
+    #select HAVE_GPIO_ADC
 
 config BOARD_DIRECTORY
     string