read antenna diversity and combining information from the EEPROM.
Enable antenna diversity/combining feature only when both LNA
diversity and fast diversity are supported
Cc: Gabriel Tseng <Gabriel.Tseng@Atheros.com> Cc: Senthilkumar Balasubramanian <Senthilkumar.Balasubramanian@Atheros.com> Tested-by: Mohammed Shafi Shajakhan <mshajakhan@atheros.com> Signed-off-by: Mohammed Shafi Shajakhan <mshajakhan@atheros.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>