iio: inv_mpu6050: Use i2c_acpi_get_i2c_resource() helper

ACPI provides a generic helper to get I2C Serial Bus resources.
Use it instead of open coded variant.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>