staging: wlan-ng: hfa384x.h: Use endian type in 'hfa384x_link_status' struct

The 'linkstatus' field from struct 'hfa384x_link_status' represents a
16-bit little-endian integer, so declare it as such to avoid the
following sparse warning when accessing it through the 'le16_to_cpu()'
function:

 prism2sta.c:1450:31: warning: cast to restricted __le16

Signed-off-by: Ricardo Silva <rjpdasilva@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>