scsi: core: Improve scsi_vpd_inquiry() checks

scsi: core: Improve scsi_vpd_inquiry() checks

Some USB-SATA adapters have broken behavior when an unsupported VPD page is
probed: Depending on the VPD page number, a 4-byte header with a valid VPD
page number but with a 0 length is returned. Currently, scsi_vpd_inquiry()
only checks that the page number is valid to determine if the page is
valid, which results in receiving only the 4-byte header for the
non-existent page. This error manifests itself very often with page 0xb9
for the Concurrent Positioning Ranges detection done by sd_read_cpr(),
resulting in the following error message:

sd 0:0:0:0: [sda] Invalid Concurrent Positioning Ranges VPD page

Prevent such misleading error message by adding a check in
scsi_vpd_inquiry() to verify that the page length is not 0.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Link: https://lore.kernel.org/r/20230322022211.116327-1-damien.lemoal@opensource.wdc.com
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>