iwlagn: fix microcode error on 4965

Commit dbbf1755b09eef8ff6dd21c8dafe1606f051ce12 "iwlwifi: use
antenna information in EEPROM" caused 4965 device breakage with
"Microcode SW error detected.  Restarting 0x82000000." message.
This patch reverts 4965 part of that commit.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>