ipath_verbs_register_sysfs() never returned the correct error
code from device_create_file and never cleaned up from a failure.
Additionally, the caller of ipath_verbs_register_sysfs() doesn't
return the correct "ret" value.

This patch resolves all of these issues.
Reported-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Reviewed-by: NDean Luick <dean.luick@intel.com>
Signed-off-by: NMike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>