Staging: iio: accel: adis16201: Rename few macro definitions

Rename the macro definitions with suitable names specifying their
purpose.

* ADIS16201_STARTUP_DELAY_MS: Remove the comment specifying the delay in
  microseconds and rename it with addtition of _MS suffix.

* ADIS16201_MSC_CTRL_ACTIVE_DATA_RDY_HIGH: Rename the macro to make it
  similar to other misc control registers which denotes the data ready
  polarity.

* ADIS16201_DIAG_STAT_FLASH_UPT_FAIL_BIT: Rename to denote it is a
  failure bit.

* ADIS16201_GLOB_CMD_FACTORY_RESET: Remove ambiguous _CAL suffix and add
  _RESET suffix instead to denote factory reset command.

Signed-off-by: Himanshu Jha <himanshujha199640@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>