iwlwifi: mvm: remove debugfs hook for reduced tx power

This was not used is unlikely to be used, just kill it.

Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

diff --cc drivers/net/wireless/iwlwifi/mvm/coex.c
Simple merge

diff --cc drivers/net/wireless/iwlwifi/mvm/debugfs-vif.c
Simple merge

diff --cc drivers/net/wireless/iwlwifi/mvm/mvm.h
Simple merge

diff --cc drivers/net/wireless/iwlwifi/mvm/sta.h
Simple merge