[SCSI] fnic: host reset returns nonzero value(errno) on success

Fixed appropriate error codes that returns negative error number on failure,
and 0 on success. fnic_reset() is used directly by the fc transport callback
issue_fc_host_lip which requires a negative error number on failure.

Signed-off-by: Narsimhulu Musini <nmusini@cisco.com>
Signed-off-by: Hiral Patel <hiralpat@cisco.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>