scsi: ufs: core: Remove unused field in struct ufs_hba

Remove unused fields 'rpm_lvl_attr' and 'spm_lvl_attr' in struct ufs_hba.
Commit cbb6813e ("scsi: ufs: sysfs: attribute group for existing sysfs
entries.") removed all code using that field.

Link: https://lore.kernel.org/r/413601558.101648105683746.JavaMail.epsvc@epcpadp4


Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Keoseong Park <keosung.park@samsung.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>