Set Block Data Update bit

[caternuson]

This fixes an issue that was originally brought up in emails. Adds setting of the Block Data Update bit for the ISM330DHCX and LSM6DS3TRC.

This was already in place for other sensor variants, so only added some code comments to those.

Example test for ISM330DHCX:

#include <Adafruit_ISM330DHCX.h>

Adafruit_ISM330DHCX ism330dhcx;

void setup(void) {
  Serial.begin(115200);
  while (!Serial);
  Serial.println("Adafruit ISM330DHCX test!");

  if (!ism330dhcx.begin_I2C()) {
    Serial.println("Failed to find ISM330DHCX chip");
    while (1);
  }
  Serial.println("ISM330DHCX Found!");

  ism330dhcx.setAccelRange(LSM6DS_ACCEL_RANGE_4_G);
  ism330dhcx.setGyroRange(LSM6DS_GYRO_RANGE_1000_DPS);

  ism330dhcx.setAccelDataRate(LSM6DS_RATE_6_66K_HZ);
  ism330dhcx.setGyroDataRate(LSM6DS_RATE_6_66K_HZ);
}

void loop() {
  sensors_event_t accel;
  sensors_event_t gyro;
  sensors_event_t temp;
  ism330dhcx.getEvent(&accel, &gyro, &temp);

  Serial.print(gyro.gyro.x);
  Serial.print(","); Serial.print(gyro.gyro.y);
  Serial.print(","); Serial.print(gyro.gyro.z);
  Serial.println();
}

BEFORE

AFTER

[caternuson]

@ladyada for review

[ladyada]

lovely!

[ladyada]

cc @pBerthold