staging: rtl8188eu: fix usage of uninit scalar in rtw_drv_init()

Function rtw_drv_init() is written in a way that assumes 'status' != _SUCCESS
as long as not explicitly set. Thus initialize 'status' to FAIL, in order to
prevent undefined behaviour if going through the exit paths. Detected by
Coverity - CID 1077832.

Signed-off-by: Christian Engelmayer <cengelma@gmx.at>
Acked-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>