Add support for CEVA BNO08x 9DoF sensor (#809)

* Add support for CEVA BNO08x 9DoF sensor. Also includes implementation of CEVA SH-2 and SHTP protocols.

* Replace machine.I2C with drivers.I2C interface to remove dependency on machine package

* Replace Pin functionality with that provided by tinygo.org/x/drivers/internal/pin

* Unexport fields on SensorValue and replace with accessor methods. Add check for correct SensorID validation

* Add example to smoketest.sh

* Change build target for smoketest to match development environment.. Probably not important, but matches reality.

* Fix decoding of some sensor data: Step Counter, Tap Detector, Flip Detector. These are experimental.

* Refactor to allow SPI/UART etc. SPI is currently under development, but is omitted from this commit.

Example code has been moved to i2c subdirectory.

This commit introduces some major refactoring changes. It introduces a "Buser" interface and tries to remove any I2C specific code from the core. It still retains a couple of I2C specific fields in the "Config" struct ("Address" and "ReadChunk") but they are ignored in the as yet uncommited SPI code.

* Fix CRLF -> LF for gofmt

* Update smoketest to point to new example file

examples/bno08x/i2c/main.go

@@ -0,0 +1,66 @@
+// Package main provides a basic example of using the BNO08x driver
+// to read rotation vector (quaternion) data from the sensor.
+package main
+
+import (
+	"machine"
+	"time"
+
+	"tinygo.org/x/drivers/bno08x"
+)
+
+func main() {
+	time.Sleep(2 * time.Second) // Wait for sensor to power up
+	// Initialize I2C bus
+	i2c := machine.I2C0
+	err := i2c.Configure(machine.I2CConfig{
+		Frequency: 400 * machine.KHz,
+	})
+	if err != nil {
+		println("Failed to configure I2C:", err.Error())
+		return
+	}
+
+	println("Initializing BNO08x sensor...")
+
+	// Create and configure sensor using I2C
+	sensor := bno08x.NewI2C(i2c)
+	err = sensor.Configure(bno08x.Config{})
+	if err != nil {
+		println("Failed to configure sensor:", err.Error())
+		return
+	}
+
+	println("Sensor initialized successfully")
+
+	// Enable Game Rotation Vector reports at 100Hz (10000 microseconds = 10ms interval)
+	// Using Game Rotation Vector (0x08) to match the working channel_debug test
+	err = sensor.EnableReport(bno08x.SensorGameRotationVector, 10000)
+	if err != nil {
+		println("Failed to enable game rotation vector:", err.Error())
+		return
+	}
+
+	println("Reading rotation vectors...")
+	println("Format: Real I J K Accuracy")
+
+	// Add a delay after enabling reports (Arduino does this)
+	time.Sleep(100 * time.Millisecond)
+
+	// Main loop - read and display quaternion data
+	for {
+		event, ok := sensor.GetSensorEvent()
+		if ok && (event.ID() == bno08x.SensorRotationVector || event.ID() == bno08x.SensorGameRotationVector) {
+			q := event.Quaternion()
+			if event.ID() == bno08x.SensorRotationVector {
+				println(q.Real, q.I, q.J, q.K, event.QuaternionAccuracy())
+			} else {
+				// GameRotationVector doesn't have accuracy
+				println(q.Real, q.I, q.J, q.K)
+			}
+		}
+
+		// Arduino uses 10ms delay in loop
+		time.Sleep(10 * time.Millisecond)
+	}
+}