scsi: ufs: core: Fix invalid probe error return value

After DME Link Startup, the error return value is set to the MIPI UniPro
GenericErrorCode which can be 0 (SUCCESS) or 1 (FAILURE).  Upon failure
during driver probe, the error code 1 is propagated back to the driver
probe function which must return a negative value to indicate an error,
but 1 is not negative, so the probe is considered to be successful even
though it failed.  Subsequently, removing the driver results in an oops
because it is not in a valid state.

This happens because none of the callers of ufshcd_init() expect a
non-negative error code.

Fix the return value and documentation to match actual usage.

Fixes: 69f5eb7 ("scsi: ufs: core: Move the ufshcd_device_init(hba, true) call")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251024085918.31825-5-adrian.hunter@intel.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: ahunter6

drivers/ufs/core/ufshcd.c

@@ -10656,7 +10656,7 @@ static int ufshcd_add_scsi_host(struct ufs_hba *hba)
  * @mmio_base: base register address
  * @irq: Interrupt line of device
  *
- * Return: 0 on success, non-zero value on failure.
+ * Return: 0 on success; < 0 on failure.
  */
 int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 {
@@ -10897,7 +10897,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	hba->is_irq_enabled = false;
 	ufshcd_hba_exit(hba);
 out_error:
-	return err;
+	return err > 0 ? -EIO : err;
 }
 EXPORT_SYMBOL_GPL(ufshcd_init);