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: 69f5eb78d4b0 ("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>