Samsung msm7x27: add support for kernel 3.0, ath6kl-compat driver

Notes:
 - this patch enables opt-in support for kernel 3.0 and ath6kl-compat
   wifi. Can be enabled by setting the following in device_name.mk:
   BUILD_WITH_30X_KERNEL := true
   BOARD_WLAN_DEVICE := ath6kl_compat
 - the change to wpa_supplicant service will not negatively affect the
   ar6000 driver with wext. Invoking "-Dnl80211,wext" will instruct
   wpa_supplicant to try nl80211, and then fallback to wext. If nl80211
   is not compiled-in, it will automatically use wext, just as before.
 - wpa_supplicant_8_lib is added for ath6kl-compat driver; fully supports
   regular station mode and ad-hoc mode (using compiled hostapd).

Change-Id: I0356a148da042bfbca355b2b7a56095500995fb9