staging/rdma/hfi1: Return early from hfi1_ioctl parameter errors

Rather than have a switch in a large else clause make the parameter checks
return immediately.
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>