pds_core: Fix documentation for pds_client_register

The documentation above pds_client_register states that it returns 0 on
success and negative on error. However, it actually returns a positive
client ID on success and negative on error. Fix the documentation to
state exactly that.

Signed-off-by: Brett Creeley <[e-mail]>
Signed-off-by: Shannon Nelson <[e-mail]>
Reviewed-by: Jesse Brandeburg <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/ethernet/amd/pds_core/auxbus.c

···
  * @pf_pdev:	ptr to the PF driver struct
  * @devname:	name that includes service into, e.g. pds_core.vDPA
  *
- * Return: 0 on success, or
+ * Return: positive client ID (ci) on success, or
  *         negative for error
  */
 int pds_client_register(struct pci_dev *pf_pdev, char *devname)