This update the register initialization/reset values (aka initvals)
for ar9271 based on the last recommended values on 2009-06-04 by our
systems engineering team.

The changes account for:

  * Supporting ar9271 1.0 and ar9271 1.1 together, the difference
    is bb_spectral_scan_ena, for 1.0 we'll set this to 0x1.

  * Ensuring we get the correct noise floor values -115 ~ -118
    when we enable bb_enable_ant_div_lnadiv=0 and
    mc_tx_def_ant_sel=1. Previous to this we would get noise
    floor values in the range -50 ~ -80. To fix settings for
    the registers:

     - bb_ch1_xatten1_db
     - bb_ch1_xatten2_db
     - bb_ch1_xatten1_margin
     - bb_ch1_xatten2_margin
     - bb_ch1_gain_force
     - bb_ch1_xatten2_hyst_margin
     - bb_ch1_xatten1_hyst_margin
     - bb_ch1_max_oc_gain

  * 0x8120[2] mc_mic_new_location_enable is changed to 0x1. The MAC team
    suggest to set this value.

  * 0x9910[0] bb_spectral_scan_ena is changed to 0x0.
    For ar9271 1.1 we don't need to enable this bit.

Cc: Stephen Chen <Stephen.Chen@atheros.com>
Signed-off-by: NLuis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>