scsi: target: tcmu: Fix warning: 'page' may be used uninitialized

mainline inclusion
from mainline-v5.10-rc1
commit 8c4e0f21
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5SXLB
CVE: NA

--------------------------------

Corrects drivers/target/target_core_user.c:688:6: warning: 'page' may be
used uninitialized.

Link: https://lore.kernel.org/r/20200924001920.43594-1-john.p.donnelly@oracle.com


Fixes: 3c58f737 ("scsi: target: tcmu: Optimize use of flush_dcache_page")
Cc: Mike Christie <michael.christie@oracle.com>
Acked-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: John Donnelly <john.p.donnelly@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Wenchao Hao <haowenchao@huawei.com>
Reviewed-by: lijinlin <lijinlin3@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>