sensor: axis-align: Add helper API to align for fetch-get

[ubieda]

For backwards compatibility support. Assuming double[3].

Tested by adding the following code in imu zros-driver:

		...
		sensor_sample_fetch(ctx->accel_dev);
		sensor_channel_get(ctx->accel_dev, SENSOR_CHAN_ACCEL_XYZ, accel_value);
		for (int j = 0; j < 3; j++) {
			ctx->accel_raw[j] = sensor_value_to_double(&accel_value[j]);
		}
		if (axis_ref) {
			sensor_three_axis_ref_align_fp(axis_ref, ctx->accel_raw);
		}
		...

[PetervdPerk-NXP]

Could you do the axis alignment on the raw struct sensor_value instead of doubles, this generates either a vmul.f64 or vneg.f64 cpu instruction which is quite costly.

Also we I would consider unrolling the loop to help the CPU pipeline.

[ubieda]

@PetervdPerk-NXP I can make the change - Although I'm concerned that most if not all floating-point operations in Cerebri are done with doubles. Wouldn't that be a much higher problem?

[ubieda]

Could you do the axis alignment on the raw struct sensor_value instead of doubles, this generates either a vmul.f64 or vneg.f64 cpu instruction which is quite costly.

Also we I would consider unrolling the loop to help the CPU pipeline.

@PetervdPerk-NXP PTAL with these new updates. Should meet your previous change-requests.