iwlwifi: consider HE capability when setting LDPC

The AP may set the LDPC capability only in HE (IEEE80211_HE_PHY_CAP1),
but we were checking it only in the HT capabilities.

If we don't use this capability when required, the DSP gets the wrong
configuration in HE and doesn't work properly.

Signed-off-by: Mordechay Goodstein <mordechay.goodstein@intel.com>
Fixes: befebbb3

 ("iwlwifi: rs: consider LDPC capability in case of HE")
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20200306151128.492d167c1a25.I1ad1353dbbf6c99ae57814be750f41a1c9f7f4ac@changeid