ath9k: Avoid OF no-eeprom quirks when no qca,no-eeprom

ath9k: Avoid OF no-eeprom quirks when no qca,no-eeprom

Based on the process of discovery in
https://github.com/openwrt/openwrt/pull/1613, it has become clear
that (at least) the PowerCloud System CR5000 was unable to get
working 5GHz wireless (PCIe) because AH_USE_EEPROM was unconditionally
masked out, not only when qca,noeeprom was in the DTS.

This patch moves mask AH_USE_EEPROM into the if ... qca,noeeprom
OF test.

Thanks to Christian Lampartar (@chunkeey) for the heavy lifting and help.

Patch has been prepared for upstream and will be submitted after review
by @chunkeey and @xdarklight.

Signed-off-by: Daniel F. Dickinson <cshored@thecshore.com>