iwlagn: use 6000g2b uCode for 130 series devices

For 130 series device, 6000g2b uCode will be used, no need to
have additional defines for 130 devices, so remove those.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>