iio: imu: inv_mpu6050: Check ACPI companion directly

Instead of checking for ACPI handle followed by extracting a companion
device, do the latter first and use it for checks.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220203155920.18586-2-andriy.shevchenko@linux.intel.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>