scsi: csiostor: add a check for NULL pointer after kmalloc()

[ Upstream commit 89809b02 ]

Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Varun Prakash <varun@chelsio.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>