iwlwifi: use antenna information in EEPROM

The valid tx/rx antenna information is part of EEPROM, so use it
to configure the device.

For few cases, the EEPROM did not reflect the correct antenna, but
it is too late to modify the EEPROM, so overwrite with .cfg parameters

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>