staging: rtl8712: changed struct members to __le32

Fixed sparse warning "cast to restricted __le32".
struct sitesurvey_parm uses little endian members.

Signed-off-by: Jannik Becher <becher.jannik@gmail.com>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>