scsi: libfc: remove set but not used variable 'rpriv'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/scsi/libfc/fc_fcp.c: In function 'fc_queuecommand':
drivers/scsi/libfc/fc_fcp.c:1875:30: warning:
 variable 'rpriv' set but not used [-Wunused-but-set-variable]

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Johannes Thumshirn <jth@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>