scsi: ufs: core: Fix a possible use before initialization case

In ufshcd_exec_dev_cmd(), if error happens before lrpb is initialized, then
we should bail out instead of letting trace record the error.

Link: https://lore.kernel.org/r/1623227044-22635-1-git-send-email-cang@codeaurora.org
Fixes: a45f9371

 ("scsi: ufs: Optimize host lock on transfer requests send/compl paths")
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>