scsi: ufs: Use designated initializers in ufs_pm_lvl_states[]

The comments in the enum ufs_pm_level definition are redundant. Remove the
comments from the ufs_pm_level enum and use designated initializers in the
ufs_pm_lvl_states[] definition instead.

Link: https://lore.kernel.org/r/20210519202058.12634-3-bvanassche@acm.org
Cc: Stanley Chu <stanley.chu@mediatek.com>
Cc: Can Guo <cang@codeaurora.org>
Cc: Bean Huo <beanhuo@micron.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>