scsi: scsi_debug: Fix a warning in resp_report_zones()

scsi: scsi_debug: Fix a warning in resp_report_zones()

As 'alloc_len' is user controlled data, if user tries to allocate memory
larger than(>=) MAX_ORDER, then kcalloc() will fail, it creates a stack
trace and messes up dmesg with a warning.

Add __GFP_NOWARN in order to avoid too large allocation warning.  This is
detected by static analysis using smatch.

Fixes: 7db0e0c8190a ("scsi: scsi_debug: Fix buffer size of REPORT ZONES command")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Link: https://lore.kernel.org/r/20221112070612.2121535-1-harshit.m.mogalapalli@oracle.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>