[ath9k-devel] ath9k: extend and improve handling of ath9k_platform_data

This series improves handling of ath9k_platform_data inside ath9k. A
quick summary of the changes is:
- led_active_high can now be configured via ath9k_platform_data:
  This change is based on a patch originally written by Vittorio
  Gambaletta which is part of OpenWrt's ath9k patches.
- small code cleanups which include removal of unused variables,
  return values duplicate code (no functional changes)
- ath9k_hw_init_macaddr will not change common->macaddr anymore
  to make it independent of whether it's called before or after
  ath9k_platform_data initialization in init.c
- initialization based on ath9k_platform_data in init.c is now
  easier to understand (no functional changes)

Patch 6 from this series supersedes the following patch by Eduardo
Abinader: "ath9k: return false when reading wrong eeprom offset" [0]


[0] https://patchwork.kernel.org/patch/9181371/