lsm6ds3: update comment for clarity
Add more comment for who am i registers since the name for st parts and
who am i register does not seem to mix well.
BRANCH=none
TEST=none
/* Who Am I */
#define LSM6DSM_WHO_AM_I_REG 0x0f
+/* LSM6DSM/LSM6DSL/LSM6DS3TR-C */
#define LSM6DSM_WHO_AM_I 0x6a
+/* LSM6DS3 */
#define LSM6DS3_WHO_AM_I 0x69
#define LSM6DSM_CTRL1_ADDR 0x10
