scsi: ufs: Remove is_rpmb_wlun()

Commit edc0596c ("scsi: ufs: core: Stop clearing UNIT ATTENTIONS")
removed all callers of is_rpmb_wlun(). Hence also remove the function
itself.

Link: https://lore.kernel.org/r/20211203231950.193369-4-bvanassche@acm.orgReported-by: Nkernel test robot <lkp@intel.com>
Tested-by: NBean Huo <beanhuo@micron.com>
Reviewed-by: NAsutosh Das <asutoshd@codeaurora.org>
Reviewed-by: NAlim Akhtar <alim.akhtar@samsung.com>
Reviewed-by: NBean Huo <beanhuo@micron.com>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufshcd.c

@@ -2650,11 +2650,6 @@ static inline u16 ufshcd_upiu_wlun_to_scsi_wlun(u8 upiu_wlun_id)
 	return (upiu_wlun_id & ~UFS_UPIU_WLUN_ID) | SCSI_W_LUN_BASE;
 }
 
-static inline bool is_rpmb_wlun(struct scsi_device *sdev)
-{
-	return sdev->lun == ufshcd_upiu_wlun_to_scsi_wlun(UFS_UPIU_RPMB_WLUN);
-}
-
 static inline bool is_device_wlun(struct scsi_device *sdev)
 {
 	return sdev->lun ==