drivers/net/wireless: need consider the not '\0' terminated string.

  in ray_cs.c:
    the a_current_ess_id is "Null terminated unless ESSID_SIZE long"
    so we need buffer it with '\0' firstly, before using strlen or %s.

  additional information:
    in drivers/net/wireless/rayctl.h:
      "NULL terminated unless 32 long" is a comment at line 616, 664
      ESSID_SIZE is 32, at line 190
    in include/uapi/linux/wireless.h:
      IW_ESSID_MAX_SIZE is also 32
    in drivers/net/wireless/ray_cs.c:
      use strncpy for it, without '\0' terminated, at line 639
      use memcpy for it, assume not '\0' terminated in line 1092..1097
      buffer it with '\0' firstly, before using %s, in line 2576, 2598..2600

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>