iio: imu: bno055: fix OOB access of hw_xlate array

In the Linux kernel, the following vulnerability has been resolved: iio: imu: bno055: fix OOB access of hw_xlate array Fix a potential out-of-bounds array access of the hw_xlate array in bno055.c. In bno055_get_regmask(), hw_xlate was iterated over the length of the vals array instead of the length of the hw_xlate array. In the case of bno055_gyr_scale, the vals array is larger than the hw_xlate array, so this could result in an out-of-bounds access. In practice, this shouldn't happen though because a match should always be found which breaks out of the for loop before it iterates beyond the end of the hw_xlate array. By adding a new hw_xlate_len field to the bno055_sysfs_attr, we can be sure we are iterating over the correct length.