ath9k: add support for endian swap of eeprom from platform data

On some devices (especially little-endian ones), the flash EEPROM data
has a different endian, which needs to be detected.
Add a flag to the platform data to allow overriding that behavior

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --cc drivers/net/wireless/ath/ath9k/eeprom_def.c
Simple merge

diff --cc drivers/net/wireless/ath/ath9k/hw.h
Simple merge

diff --cc drivers/net/wireless/ath/ath9k/init.c
Simple merge

diff --cc include/linux/ath9k_platform.h
Simple merge