scsi: core: Avoid printing an error if target_alloc() returns -ENXIO

scsi: core: Avoid printing an error if target_alloc() returns -ENXIO

Avoid printing a 'target allocation failed' error if the driver
target_alloc() callback function returns -ENXIO. This return value
indicates that the corresponding H:C:T:L entry is empty.

Removing this error reduces the scan time if the user issues SCAN_WILD_CARD
scan operation through sysfs parameter on a host with a lot of empty
H:C:T:L entries.

Avoiding the printk on -ENXIO matches the behavior of the other callback
functions during scanning.

Link: https://lore.kernel.org/r/20210726115402.1936-1-sreekanth.reddy@broadcom.com
Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>