Add optional BMA456 accelerometer init on shared I2C bus.

Probe and configure the sensor when present; log and continue boot if
init fails so boards without BMA456 still run normally.

Co-authored-by: Cursor <cursoragent@cursor.com>

components/bma456/README.md

@@ -0,0 +1,58 @@
+# BMA456 Sensor API
+
+> This package contains SensorAPIs for BMA456 Sensor
+
+## Sensor Overview
+
+The BMA456 is an ultra-small, triaxial, low-g acceleration sensor with digital interfaces, aiming for low-power consumer electronics applications. Featuring 16 bit digital resolution and embedded intelligence, the device is optimized to fulfill low power accelerometer requirements.
+
+## Applications
+
+### BMA456W
+- Any motion
+- No motion 
+- Step detector
+- Step counter
+- Step activity
+- Tap
+	- Single tap
+	- Double tap
+
+### BMA456H
+
+- Any motion
+- No motion 
+- Step detector
+- Step counter
+- Step activity
+- Auto low power
+- Tap
+	- Single tap
+	- Double tap
+	- Triple tap
+
+### BMA456MM
+
+- Any motion
+- No motion 
+- Orientation
+- High-g
+- Low-g
+- Significant motion
+- Auto low power
+- Tap
+	- Single tap
+	- Double tap
+	- Triple tap
+
+### BMA456AN
+
+- Any motion
+- No motion
+
+### BMA456 tablet
+
+- Any/no motion 
+- Low-g
+- Single, double and triple tap
+- Orientation