iio: imu: inv_mpu6050: Fix alignment with open parenthesis

This makes code consistent around inv_mpu6050 driver and
fixes the following checkpatch.pl warning:
CHECK: Alignment should match open parenthesis

Note that there were few cases were it was not possible to
fix this due to making the line too long, but we can live with that.

Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>