staging: slicoss: use status in slic_if_init

While initializing the interface if we are not able to setup the command
to UP the link then we release everything and return the error code.

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>