scsi: lpfc: Do not abuse UUID APIs and LPFC_COMPRESS_VMID_SIZE

scsi: lpfc: Do not abuse UUID APIs and LPFC_COMPRESS_VMID_SIZE

The lpfc_vmid_host_uuid is not defined as uuid_t and its usage is not the
same as for uuid_t operations (like exporting or importing).  Hence replace
call to uuid_is_null() by respective memchr_inv() without abusing casting.

With that, replace LPFC_COMPRESS_VMID_SIZE with plain number and respective
sizeof() to make code robust to changes in the future, if any.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230818155452.875781-1-andriy.shevchenko@linux.intel.com
Reviewed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>